Only a Prime
by Borath
Summary: The Prime stands for more than himself. With their species dwindling, the All Spark destroyed and himself having died once already, Optimus decides that there cannot be only him any longer. - Mechpreg -
1. Chapter 1

_Scratching my mechpreg itch with this one, as well as having my first go with 'sticky' biology for the Transformers. Warnings for angst in later chapters._

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><p><span>Only a Prime<span>

_Chapter One_

It was a phrase that recurred throughout Cybertronian lore, now lost with the destruction of the All Spark. _Only a Prime_ could defeat the Fallen, and Optimus had had to be resurrected as the last one to do it. There was no telling what else lay ahead that only one of his line could affect. More than that, the Primes had stood since antiquity as symbols larger than themselves: encapsulating an ideal, an archetype, a single-minded commitment to safeguard life and liberty throughout the universe. Optimus professed to the Autobots that he was just another mech - last to be attended by Ratchet if others needed him more, and first into battle no matter how unfavourable the odds. But he was also a Prime, the last, and he had died once already. Next time, fate might not be so kind.

Optimus had led Ratchet away from the Diego Garcia base to speak, miles into the clear desert where even Ironhide would not hear of it. What he proposed would change everything, had done by its mere suggestion, and now he watched the medic's back where he stood agitated and thinking. He'd made his case, argued his side, and now he waited to see how much more pushing he needed to do to get his long-time friend to agree despite his great reservations.

After twenty minutes of silence, when the sand being stirred into his vents began to become irritating, Optimus finally approached the medic. "I know it is asking a great deal, but it is my choice, and for the good of us all."

Ratchet turned partially to meet him with bright optics. They shuttered briefly, weary, before he shifted his feet to face the Prime entirely. "The risks involved," he began, trailing off with gritted dentals and averting his gaze.

It occurred to Optimus that this level of cautious protectiveness regarding his safety had increased after the Fallen. After the forest. The reminder that, despite his value as a Prime, he was still a mortal mech had shaken the Autobots, and there was a growing belief that it made more tactical sense to shield him from danger than to try to end the war quickly. Optimus was staunchly against this, but it had underlined the point: there could not only be one.

"The risks are to me alone, Ratchet," he reminded softly, speaking beneath the medic's sharper tones. "I have almost passed into the Well once already, and will do so again, permanently, at any time. Without the All Spark, a new Prime spark cannot be kindled. But with my own-"

"This could fail at every turn," Ratchet cut in, and realized the moment he'd said it that he'd already laid the foundations in his processor to agree. It was nigh-impossible to deny the Prime when he had his spark committed to an idea. It was why he had led them on the losing side for so long, and why they'd stayed to protect the humans though the order to had died with him. And it would be a greater blow to the Autobots in the future to have lost the last Prime, as well as Optimus himself.

Brushing a hand across his optics, Ratchet spoke into the heel of his hand, trying to stop his processor from visualising the disastrous variables. "If I could stimulate your spark to bud a strong enough haploid, it would need to gestate as a normal carriage, and there is a reason why Primes have been made, not born. The power they demand will decimate a normal femme."

Optimus nodded fractionally, and his voice was even. "Which is why I have decided to do it myself. You can build a gestation chamber, and given enough time, there's no reason why you couldn't find a way to graft it onto my systems."

Ratchet huffed through his vents with a low sound, arms folding stiff across his chassis. "No reason, my aft. Replacing a gestation chamber is one thing, but building one for a system that has no business being connected to it is another entirely. I'd need to install all new feeds to your spark casing, new assimilation protocols for the physical growth, rearrange your systems so that we can get the thing back out once it's grown, and then there's the rest."

Behind the face plate, hidden from view, Optimus's mouth pulled into a thin, almost grim smile. "But you can do it."

A beat before the medic shifted his weight in the sand, sighing. "Given the time, and against my better judgement, yes."

"Thank you, Ratchet. I know this will be difficult for you, for us both, but there is no other way," Optimus affirmed, touching a hand to the shorter mech's shoulder. When he began to draw his hand away to begin returning to the base, Ratchet's fingers closed about his wrist.

"I'm good, but I can't work miracles," Ratchet went on, more strength in his words as he fell back into his usual acerbic tones. "This can't be an immaculate conception. You're going to need another bot."

Optimus shifted his hand so that his thumb crossed into Ratchet's palm, squeezing once before drawing his arm back. "I was going to ask if you would consider being the other creator." The naked emotion on the medic's face to that statement suddenly brought forth a wave of awkwardness, and it was an effort to keep holding his gaze. He couldn't entirely suppress the sigh through his vents. "Anyone else's judgement would be clouded if they knew I was carrying, let alone if it were their own offspring, and that will cost lives in battle. You have long been able to partition your emotional attachments from your job, and, I need the other creator to be strong."

Ratchet arched a brow, his voice dry and not belaying any of the myriad of feelings clamouring for dominance in his spark. Honour and anxiety were both close to the top. "And you want as few to know about this little gambit of yours as possible. That is, just us."

It wasn't automatic, but the retraction of his faceplate was triggered by something instinctual; some sense that a gesture of openness to the extent of vulnerability was appropriate and, perhaps, required at this moment. There had never been any intimacy or desire between them – only a mutual respect and platonic kinship. Optimus chose his words carefully, but with a privately reassuring ease. "You are one of my oldest friends and comrades. It would gratify me to create a new life with you."

Another pause as Ratchet moved a few paces forward to stand alongside Optimus, though facing the other way, towards the base. Even with a gestation chamber, they were both mechs, so interfacing to conceive wasn't a possibility – and he wasn't going to begin speculating upon the unnecessary and psychologically treacherous route of installing a valve. No – it would be entirely clinical, conducted more in the lab than in a berth, which stunted that potential awkwardness. And Optimus was right about his ability to disassociate from what needed to be done.

But still, it was an enormous commitment, even whilst strictly platonic. "It'll take months for me to gather the right materials let alone build a chamber. There's no reason why during that time you couldn't court-"

Optimus held up a hand, the flicker of pain in his features visible purely because of the absence of the mask. "This may not work. It's dangerous, and a great deal can go wrong at any time." He paused, cycling a breath. This idea had been on his processor from a few weeks after returning from Egypt, and the worst case scenarios for almost as long. He didn't want Ratchet to think that he hadn't considered the worst as well as the best when formulating this plan. "I can face these trials, but I fear that I'm not strong enough to support another as well. You can be impartial."

Ratchet considered that with as much honesty as he could. It was the Prime's gaze that solidified his decision in the end, and he nodded with a sigh. "Alright. Alright, we'll try."


	2. Chapter 2

_Hopefully I've addressed the sparkling/pod thing that Starscream was struggling to get to work in RotF in this chapter. Also, this is an angst fic. _

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><p><span>Only a Prime<span>

_Chapter 2_

- One year later –

Optimus examined the new component from all angles where it hung suspended in milky yellow fluid – energon diluted to keep the absorbent metals alive. It looked too small to have taken a year to construct, but now the diamond shaped chamber was finally ready for grafting. Ratchet entered the Medbay without ceremony, moving to the operating berth and beginning the final preparations for surgery.

"The Peterbuilt's in the main hanger. I'll have it brought in tomorrow when we're done so I can check your re-configuration scan." When he received no response, Ratchet paused in his preparations and looked to the mech by his workbench. Optimus was considering the chamber with dim optics, lost in thought. He came to stand alongside the taller mech, arms folded, and murmured, "Last chance to change your mind, Optimus."

A soft sound, almost a sigh, before Optimus produced a small cylinder from a shoulder hatch and held it out to the medic. "I'm ready if you are."

Ratchet nodded, scanning the contents of the container through his fingers as he carried it across to the berth. "My sample's ready as well. I'll prepare them after the chamber's in place and energise the mix. A jolt through your spark should do the rest. We're likely not going to get another significant window for recovery and observation, so it'll have to be two paradigm shifts at once."

They'd gone through the procedure a dozen times in detail, but Optimus found a diminishing comfort in the knowledge as he moved to sit on the edge of the berth. It took several minutes for him to collapse away his armour into subspace, leaving him in naked protoform for the first time since landing. This was to be a change in his fundamental being, so base that he needed to be online to consciously adjust to the change lest he go into complete system shock upon awaking to it. He lay back and settled his limbs, optics soon drawn back to the suspended chamber.

"This will take three to four hours." Coming to stand at his side, Ratchet began to feed fine transparent lines into the mech's limbs. "Removing the protomass will be very quick, as opposed to transplanting the chamber. We'll need to keep conversing throughout, and I'll be commentating on what I'm doing, as I'm doing it, and you must listen and understand. This is as much a psychological operation as it is physical."

"I understand," Optimus murmured, optics fixing on an indistinct point on the ceiling as the last monitoring and regulating connections were made. There was a pressure against the juncture of his right shoulder that turned his body heavy and numb, deactivating his pain receptors and motor functions. They were ready. He heard the medic's hands transform and kept his stare on the overhead lights.

"Making the first incision over your spark chamber," Ratchet dictated flatly, as if lecturing abstractly as opposed to coating his hands in energon breaching the protoform's covering. Thin black tubes flexing from the undersides of his wrists provided suction, actively scanning the fluid for abnormalities before it was stored in an isolated internal tank to be disposed of later.

Ratchet had long become used to working without an assistant, but there were some procedures that newly highlighted how severe that lacking was. He'd done the best he could in having everything readily close to hand, but now he could only be wary and hope Primus approved of this plan.

"I'm beginning to remove the required half-tonne of protomatter directly beneath, cauterising actively." The cut in the thin, skin-like sheath was pulled open and pinned in place to leave the wound gaping, glistening silver and secreting energon.

Carefully razing away inches of protoflesh, Ratchet didn't look away as he asked, "How are you doing?"

The Prime could feel pressure and tugging, but no pain and certainly no sensations that would suggest that chunks of his body were being cut out. "I'm well," he replied softly, optics shuttering as he tried to guide his processor away from imagining the wound being bored out of him. He understood that it was important to remain aware, but he did not want to actively picture the procedure as it was being performed and described. "What explanation did you give for my time off in the end?"

Ratchet didn't respond for a full minute, optics bright with concentration as he cut deeper into the silver flesh. It came away in slab-like chunks, blackened and coarse from the cauterizing heat of the laser. "I blamed it on your resurrection bringing you back but not fully undoing all the damage that led to your death. Not a wound, exactly, but an abnormality in your protoform that requires significant enough surgery to necessitate rescanning an alt form and keeping away from combat for a few days."

A soft sound. "I notified NEST that I would need six days to recuperate fully, but I did not go into any specifics." He onlined his optics and immediately saw Ratchet lifting away a glistening piece of protoflesh. It made the mutilation they had been planning for months real, and his soft vents exhaled shakily. As much as he wanted to, he couldn't look away from it. "Lennox is going to request that the Autobots have access to the facility in the Hoover dam where the All Spark was held for additional protection."

Ratchet smiled a little, dry and faint as he added to the growing pile in the tray. "Having you laid up is very nearly a national emergency for the humans, especially if the Decepticons somehow get wind of it."

It would have been impossible to carry this out without taking Megatron into account. They had waited weeks for a significant enough skirmish that would leave the Decepticons licking their wounds for a few days, giving Optimus a window of inactivity for the post-op recovery.

"Ironhide's outside," Optimus remarked softly, finally dragging his optics from the material Ratchet was lifting away.

The medic hummed. "Yes, he followed me from the Yard. I won't be surprised if he refuses a guard rota and stands outside that door until you're discharged."

"Will he be able to detect anything?"

"Not until the sparkling has grown large enough to become obvious as an energy reading." Ratchet paused in his excavations to focus on draining the leaked energon from the site, micro-sealing the breaches with brief, sizzling touches. "For the first half of carriage, it'll be an integrated part of your systems and without any isolating features. After that, its processor will begin booting up and experimenting with motor functions and the like, and then we'll have to tell them."

Optimus felt a pang at that, and suddenly wanted more than anything to be able to move his arms to rub his optics. From the neck down he was completely paralysed, and would remain so for several days until Ratchet was satisfied with the condition of the incision. In that time, he'd see no one but Ratchet lest a visitor glimpse something incriminating or bring in a contaminant that would take disastrous advantage of his exposed state. Ironhide, his bodyguard since he'd been made a Prime, was standing as close as he could get.

"Alright, I've cleared the space and prepared it for grafting," Ratchet finally uttered, breaking his thoughts as he set aside the tray of detritus. "I've neutralized the self-repair nanites in this area so that they won't re-generate your natural protoflesh and corrupt the gestation chamber."

Irreversible. His body as he'd known it for millennia was altered. Soon he would be the first Prime able to bear new life, and that too would be irreversible. Whether they were successful now or not. Optimus waited silently, blinking in a flinch when Ratchet touched his helm and came to stand at his shoulder.

"Ready?" At the breathed affirmative, Ratchet crossed to the workbench bearing the precious cylinder and took a high-sided tray from the drawer beneath. "You must keep talking to me, Optimus. It's critical that you remain cogent and aware of the changes as they take place."

A snapped retort curled on his glossa, quickly suppressed as Optimus fought to temper his emotions. Ratchet had built a gestation chamber and cut a hole in his body, and was about to seal the chamber inside and spark him. Everything was going to change. He had no hesitations with going through with it, but this anxiety hadn't been present whilst they were speculating about a procedure that would in the future.

He shunted an exhale. "The chamber is alive already," Optimus uttered quickly, optics tracking across the imperfections in the sloped ceiling. "Why can't it support a sparkling outside of a body?"

"If we knew the answer to that, our species wouldn't be borderline extinct," came the flat reply as Ratchet broke the seal on top of the cylinder and gently lifted the contents out. "In theory, it should work: saturate the chamber with energon and compounds, regulate pressure and temperature to stimulate growth, and keep the fluids charged. But in reality, the sparklings starve to death. We can't simulate the influence of a carrier's systems any more than we can identify it. One of life's mysteries."

"Will my systems adapt?"

The medic returned with the tray bearing the chamber, setting it down on the berth beside a long thigh. "They should do. I've been flooding you with the electrolytes for months. Speaking of which, I'm going to give you something before I begin implanting the chamber. Extreme nausea is a side effect of it, but I've got a regulating line in your tank so there's no risk of you purging. Just concentrate on my voice and it'll pass in a few minutes."

Optimus said nothing, seeing more than feeling the needle pressing into his chassis above the gaping wound. Scant seconds passed before it felt like his equilibrium sensors had been thrown into his fuel tank and shaken violently. He closed his optics and gritted his dentals, but it didn't help. "How long until we know?"

Ratchet cradled the chamber in both hands, dwarfing the deceptively delicate-looking structure as he lowered it into the weeping vacuity. "I'll put eight potentials in the chamber to increase the odds, but it'll be at least a day before we know if any of them have attached to the lining and begun absorption."

Though entirely numb, Optimus had the strange sense of being able to feel the new organ as its weight settled into him, lining up with his raw protoflesh. It made the nausea overwhelming. He felt the space around his spark tighten sharply before the regulating line intervened and forced it back to a normal rhythm. Suddenly, and from nowhere, he wished that someone else was here – someone who was neither being irreversibly disfigured or doing the disfiguring.

"What if more than one latches?" he asked, needing the distraction of a voice.

Ratchet's optics flickered up from arranging the chamber, pressing fractionally on the pliant metal to line up connections and begin the long process of micro-welding them shut. "The weakest ones get aborted. Carrying one sparkling is going to be pushing the limits of your body and my expertise. I won't tempt -"

The medic cut himself off when one of the monitors flagged a silent alarm, his scanners fixing to the site before his optics had moved. Leukocyte analogues were swarming past the area he'd neutralised them in and were converging on the wound to attack the chamber. He felt Optimus watching him, though there was no way that he could be aware of the alarm aside from his behaviour. "I'm going to have to give you another dose to avoid a problem. There's nothing to worry about."

Optimus didn't have time to respond to that statement before the needle was reinserted and a fresh, curdling swell crashed through him. He sincerely wanted to purge just so that the feeling might pass. Ratchet's hands returned to their work.

Quiet fell between them for a long time whilst Ratchet concentrated and Optimus listened. Hearing was somehow worse than seeing what was being done, and it made him keen to keep Ratchet talking over the wet noises. Close to the end, when only a dozen minor structural reformats remained to do before the chamber was ready, Ratchet stepped away from the berth's edge and came to stand at his helm.

"I'm going to put you into recharge once the breach is closed and give your systems some time to adjust," he explained softly, noting with a frown the dark edges to the optics fixed on him. Sending a command to increase the charge on the energon he was feeding in, Ratchet began a quick scan at the same time he rested his knuckles against Optimus's jaw – one of the only places the mech currently had feeling in. "Tomorrow, if everything looks okay, I'll implant the zygotes and shock your spark to bud with them. I'll keep you under for that, as well."

The nod was implicit. "So, hopefully, when I come back online..."

"Hopefully," Ratchet affirmed with a soft smile, his face plates drawn. His expression shifted into something between reassurance and earnest, his hand moving fractionally to stroke the slender jaw. "But if none of them take, we just try again. For as long as you wish."

A whisper of a sigh and Optimus shuttered his optics briefly, wanting this strange and troubling period of transition to be over. "Thank you."

Ratchet harrumphed without feeling, stepping back to the wound and beginning to make the final adjustments. "I'm not the one making the sacrifices."

"But you are implicated," Optimus replied flatly, though kindly. The nausea had almost entirely passed now, and if he hadn't been connected to so many monitors ad regulators he'd have fallen into an exhausted recharge cycle. Instead he listened to the subtle movements of Ratchet's hands in his chassis, uttering a silent prayer to Primus to allow a new life to emerge from where they lay.

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><p><em>This is quite a big deviation from my usual "mpreg-style", so it'd be really good to hear how you're finding it<em>.


	3. Chapter 3

Only a Prime

_Chapter 3_

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><p>It wasn't until seventeen hours after closing the incision and inducing a recharge cycle that Ratchet deemed it safe to leave the Medbay. He'd been monitoring the mech's condition closely, vigilant for any signs of rejection following the averted autoimmune incident when the chamber was first connected. Once Optimus's own energon and fluids had begun circulating through the gestation chamber, it had only taken minor influences to naturalise the organ. It had been the first hurdle, and they'd almost fallen at it. The knowledge had stalled him from fully preparing the fertilized potentials, spending the hours watching in silent contemplating instead.<p>

Now, weary and stiff, he'd barely stepped out of the Medbay and begun to close and lock the doors before Ironhide spoke.

"How'd the surgery go?"

He didn't pay the dark mech any heed for a moment, scanning over the locking mechanisms as his optics shuttered to adjust to the natural light. The sun had set again without his notice. Satisfied with the security of the Medbay, he began to cross the Yard towards the main hanger. "Fine. There's no reason why he can't be discharged in a few days."

To Ratchet's surprise, Ironhide fell into rhythm with the medic's steps. He'd expected the other to be an immovable force outside the Medbay until Optimus was released. At present, however, in great want of Energon after a full day without refuelling, he wasn't going to query it.

Inside the main hanger, Ironhide lingered by the door. He watched with a carefully neutral expression as Ratchet drained two cubes in quick succession and picked up a third. "Been a long while since I've known anyone had to have their protoform worked on like that," he offered, pensive.

A grunt as Ratchet consumed half the cube, subspacing a fourth for later as an afterthought. "I've never seen a total resurrection before, let alone a botched one." Still avoiding the mech's watchful gaze, he rubbed the weariness from his optics with thumb and forefinger before moving deeper into the hanger. At the back he found the Peterbuilt where he had instructed it to be brought, though he considered it now with a frown. "I thought it was black," he remarked, giving it a thorough scan for contaminants and finding none.

Coming to stand alongside, Ironhide looked over the vehicle with a thin smile. His tone was soft. "Sunny gave it a paint job last night. Figured it'd be easier to have the colours as part of the scan for Prime."

"Considerate." Ratchet felt a pang at that, though couldn't entirely quantify why. Instead he flicked his scanners out in a blanket sweep, confirming his suspicion that the rest of the Autobots were staying away. It was a strange custom to remain close for certain repairs but not the most dire; as if a nearby spark-pulse could disrupt Primus's benevolence.

Ironhide broke into his thoughts by stepping forwards and hefting the vehicle up in his arms, indicating that he knew full well that Ratchet had intended to carry it. Without transformation components, protoform and hefty armour incorporated into its structure, it weighed very little to him. "Finish refueling, Doc," he instructed flatly, his tone leaving no room for debate. "I got this, and I want you with all pistons firing for Prime."

"Don't think that carrying that is going to get you into my Medbay," came the dry response, though Ratchet finished the cube and set the empty aside.

As though he hadn't heard, Ironhide started walking. With rolled optics, Ratchet followed. When they'd both reached the locked hanger, the dark mech maintained a possessive grip as if it would give him passage. Sharp optics lay bright on Ratchet's own. "I decontaminated myself just as well as I did this."

"I noticed," came the drawled response, and Ratchet held the dark mech's stare with a full awareness that this was a stand-off. He folded his arms, settling in for the battle of wills. Coming between a guardian and his charge was one thing, but coming between a medic and his patient was another. This had to be cut off now, though, or it would be a problem every time he left the Medbay until Optimus was out. "I can't let you in, Ironhide."

Ironhide's features twisted in a brief yet fierce frown. "Don't give me that slag. No contaminants, I ain't gonna touch anything, and no way in the Well is standing outside adequate protection whilst Prime is in protoform. Sideswipe and Sunstreaker are already on the point keeping watch."

"It's not going to make any difference to him for you to be outside," Ratchet replied evenly, though his voice was already growing terse. "Optimus is going to be under for at least another day, and I still have a lot of-"

A blast from the larger, more powerful engine cut him off; a sound between a bark and a sigh. Ironhide didn't speak immediately, however, gritting his dentals and shuttering his optics to compose his words. "This ain't for him, it's for me," he admitted softly, tightly. "I wasn't where I should have been when Megatron blasted his spark apart, and I know where I should be now. Guardian protocols are ingrained in my circuits, Ratch', and you're killing me here."

Ratchet felt the remainder of his protests evaporate in his vocaliser, matching something in the mech's expression to Optimus' as he was removing chunks of his protomatter. Much as he wanted to respect the Prime's wishes to restrict involvement with this life-changing procedure, he could see that another supporting figure was going to be more a help than a hindrance. And there was no reason for Ironhide to know the specifics, yet.

"Come on, before I regret this," he snapped with put-upon irritation, keying the door unlocked and leading them inside. Ironhide's concerns were going to be roused by his trepidation; it forced him to straighten his backstrut and approach the berth with the confidence he'd been lacking since yesterday. He slid the end of a monitoring line into his wrist.

Setting the Peterbuilt down to one side, Ironhide came around the berth to see but did not approach it without invitation. His optics brightened on the thin form, appearing utterly vulnerable without the many tonnes of armour normally shielding it. The Prime was covered in slender needles tapering into cables, periodically crackling as they made some small adjustment in the mech's systems. Running almost the length of the high point of his chassis, the incision was marbled black around the heavy staples holding the skin-like mesh closed.

"Primus."

Ratchet glanced back at the breathed remark, combing through the results of the close scan. "It looks worse than it is."

Ironhide took a step forward, watching the medic for reprimand and finally coming alongside the berth when he received none. Up-close the damage appeared even more harrowing, the line of the wound uneven and even buckled in places. There was a nauseating sense of depth to it, and his processor flashed an image of Ratchet's hands buried in this body. "Is he alright now? All fixed?"

There were only nominal fluctuations in the mech's systems, far fewer than he had been expecting. Though relieved, Ratchet could not suppress the rising anxiety that it was safe to proceed with the next phase. They were really doing this. "Not… quite. I'll need to keep a close optic, and likely there'll be more work to do in the future."

The medic was still pensive, Ironhide could see, and he felt rooted to the spot as Ratchet moved to his workbench and returned with a containment cylinder. "What was wrong with him? That the Matrix couldn't fix."

Ratchet didn't respond for several seconds, considering the cylinder in his hands with dim optics. He'd mixed their transfluids during the night in something like a daze, jolting them with the right waves of radiation and electrical charge to trigger the freefloating reproductive components to lock together wherever there was a viable fit. It surprised him now to find how many clusters there were. Inserting a wristline through the small hatch in the top of the cylinder, he drew out the strongest eight in the batch. The rest could be stored. Just in case.

"Do you know what a leukocyte actuator is?"

Ironhide shook his head fractionally when Ratchet looked up, setting the re-sealed cylinder aside to pick up a device not dissimilar to a hypodermic syringe. He positioned the tip to one side of the incision, angling the needle into the new chamber inside and inserting it slowly. There was no reason that the mech should know what a leukocyte actuator was: he'd just invented it.

"It's what keeps us protected from contaminants." Ratchet's voice fell into a dispassionate tutorial tone as he worked, re-scanning the position of the needle before beginning to inject the contents. "Everyone is sparked with the part, but Megatron put both sword and cannon through it along with his spark and even the Matrix hasn't been able to heal it right. I've removed the damaged protomass and am trying to stimulate it to regrow."

The dark mech nodded fractionally, his own optics bright with scans and fixed on the prone body between them. "Is that why I can feel your signature in there?"

Ratchet's spark gave an extra pulse at the casual query, though he knew that there was no way Ironhide could even begin to suspect what he was really doing. That there was any deception at all. He cycled his vents in a sigh as he withdrew the needle, scanning the chamber again. "It's much like an advanced version of the humans' infantile attempts with stem cells – I can turn these into anything, but only through manipulation."

All that was left now was to activate the potential clusters and hope that at least one of them latched to the chamber wall. It was the least invasive part of the whole procedure, necessitating him only to press a hand over the Prime's spark chamber. He had been laying the ground work for this critical element for weeks, and now the waiting electrolytes responded to the pulse from Ratchet's hand to trigger a reaction in the powerful spark akin to an overload. With the gestation chamber so close, it was inevitable that arcs of the surge would ripple inside and align with the waiting zygotes. It was over in seconds, but it would be hours before he would know if any of them were latched. If the Prime was carrying.

Ironhide waited in silence for long minutes after the charge had passed, watching Ratchet as he continued to monitor stoically. When the medic was satisfied and stepped back from the berth, he folded his arms with something close to relief. He had no idea what had happened, but the mech's expression greatly eased the pressure in his spark.

"Lennox and I got talking before Prime came in," he began, tracking Ratchet back to the workbench but reticent to leave the Commander's berthside himself. "NEST's got it cleared to move the Autobots into the Hoover dam permanently as soon as possible."

Dropping onto his stool at the workbench, Ratchet rested an elbow on the ledge and his jaw on his fist. He suddenly felt exhausted down to his struts, and more than anything wanted a cube or eight of High Grade. He'd already made the decision to abstain for however long it took for Optimus to deliver a Prime sparkling, however. Or relinquish the attempt.

"Optimus will be in no condition to be moved safely for at least a week," he replied, though his tone was not immediately dismissive. A corner of his processor had been occupied with concern for the Prime being in combat when they achieved a successful carriage, but the Base was far from a safe haven. They had been stationed here for longer than they were used to staying in one spot on a planet bristling with Decepticons – it was only a matter of time until they were discovered.

As if reading Ratchet's processor, Ironhide moved slowly towards the workbench. "It'll be a dedicated space, built with moving Megatron and the All Spark cube in mind. It's decently shielded and we'll have an unlimited power supply, so we can actually build and run our own equipment. Can't think of a better place for Prime's recovery."

"Which could take months," Ratchet concluded, sitting back a little as he cast his optics about the hanger. Even after years of work it was still vastly ill-equipped – another reason he'd been so hesitant to go ahead with this sparkling idea. With generators run off the dam's water, though, he could set up a fabrication mill and a smelter. Make new parts as opposed to being restricted to recycling the dead; construct better medical equipment; a dozen things that would increase their odds of delivering a sparkling safely, whilst benefiting the Autobots as a whole.

A glance to Optimus decided it. "Get me the technical specs, and tell Lennox Optimus will be fit to move by the end of the week."

Ironhide hummed an affirmative. With the Prime incapacitated, command fell to him and, as it was medical leave, Ratchet, jointly. And he foresaw no difficultly in justifying this decision to Optimus when he awoke. In his processor there was no doubt that this was a course of action that needed to be taken, and perhaps had needed to be for some time. "Two weeks to get us all packed, and with equipment we'll need to drive there in convoy."

"I'll leave you to organise the paperwork," Ratchet announced flatly, one hand drifting through an array of cabling on the workbench in search of a process-synch that would allow him to perform the alt-scan whilst Optimus was still unconscious. "More than likely, I'll be occupied here."

It was something close to helping, assuming some kind of control over an alarming turn of events, and Ironhide felt his hydraulics relax a little. Much as he hated dealing with the bureaucratic necessities of living alongside and operating within NEST, he was keen to get started with pushing this plan through the higher powers. He already had Lennox's backing, and he doubted that Secretary Keller would be difficult to convince given that a significant part of their need to move was Optimus's health. "I'll get on it in the morning."

Finding the cable but thinking better of it for tonight, Ratchet pushed to his feet with a sigh. "Go get some recharge, Ironhide. I'll be doing the same."

It would be far from the first time he'd recharged on the floor alongside a patient, linked with hardlines so that he'd be roused by the slightest fluctuation in the wrong direction. There was nothing to do now but wait and see if any of the potentials latched, and the thought of spending that time anxiously awake twisted his tanks.

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><p><em>Having a bit of a rough time with writing at the moment, so there'll likely be a long delay before this and any other story is updated. Nothing is abandoned, though: just percolating. Thank you for your patience, and for taking the time to read my work. <em>


	4. Chapter 4

_This and the next two chapters have been written in sections together, so there's nothing purely sensationalist in the (warning) character death. _

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><p><span>Only a Prime<span>

_Chapter 4_

- 5 weeks later –

The viscous fluid in the cube was more liquidated metal compounds than energon, and Optimus had to make a concerted effort to drink it as he inspected the contents of the trailer from the back. He would be towing this last load of armaments to the new Base later this afternoon, much to Ironhide's consternation. The dark mech was never far away now, and it came as no surprise when the broad shadow joined Optimus's on the warm asphalt.

"Sure this is a good idea?" Ironhide asked with narrowed optics, his expression mutually dubious and concerned. "Not fully loaded yet and it weighs almost as much as you."

Forcing down another mouthful of the medicinal broth, Optimus hummed a little to assuage the mech's fears. They had been travelling back and forth between the desert and dam bases as a kind of extended patrol, moving equipment over convoluted routes just in case the Decepticons had noticed the activity and were watching. "Far from the heaviest load I've hauled, and Ratchet believes that it might help."

Ironhide nodded fractionally, his optics physically directed towards the machinery inside the trailer but his sensors fixed on the Prime. "Berth rest didn't help, so running a bit hot might be the kick it needs," he murmured evenly, internal vents gaping in a slow sigh.

The procedure had failed twice already, and the renewed attempt he knew to be scheduled shortly hung like a weight over his spark. Ratchet had told him that this was to be a learning curve, and unlikely to work immediately. It was frustrating beyond the telling not to be able to do anything in any way helpful, reduced to waiting close and willing Primus, every time, to let this next attempt work. Ratchet seemed to be doing everything that he could, he reaffirmed, watching as Optimus drained the last of the potent cube. Just a scan of it made his gustatory sensors recoil, determining that anything of that foul a composition had to be medically good. "I don't know how you're choking that swill down."

Optimus considered the cube with a grimaced smile before holding it out to Ironhide in challenge. The shorter mech shook his head stiffly, features hardening. "If Ratchet thinks that'll help get you fixed, I'd sooner have you sucking that cube dry than anything else. Speaking of which, you've got an appointment."

"Ratchet's already sent me three pings." Finishing the last of the cube with a grimace, Optimus susbspaced the container and scanned the trailer again as a distraction from the sensorial 'taste'. The weight distribution wasn't quite right, but it would have to be a human to adjust it.

Ironhide had already picked up the same thing, and could see in the narrowing of the mech's optics and the considering tilt of his head that he'd found a potential procrastination point. "I'll make sure it's ready before you get back. There's nothing much left to do now. 'Bee and Sideswipe hit Las Vegas a few minutes ago and should be at the Base inside the hour. The kids want to look around the lights a bit, first."

"I'll have my comm.s on – keep me informed," Optimus instructed softly, meeting something in the dark mech's optics but finding them averted before he could identify it. He felt a sudden urge to touch his shoulder, to offer some kind of reassurance, but he knew that it would be of little comfort and likely make his bodyguard feel even more awkwardly useless. Ratchet was being highly adaptive in his… treatment, analyzing sensor readings and projections almost constantly and adjusting his plans and procedures accordingly. He was being kept better fuelled and maintained than he had in years, and the two early miscarriages had done no harm to his systems.

The native phrase of a third attempt being charmed to succeed came to mind/

Ratchet was already at the berthside when Optimus stepped through the closing hanger doors. It was the last one to be taken to the Hoover base, looking incongruous now in the middle of the sparse Medbay. The medic didn't look up from the long needle he was making fine adjustments to - a small gesture that Optimus appreciated as a spike of trepidation worked up into his spark.

"Did you ingest all of it?"

Optimus came to sit on the edge of the berth on the opposite side to Ratchet, not yet twisting to recline against the raised back. As before, the minutes before the procedure were awkward in a way he still couldn't explain. He felt the suppression field that would soundproof the hanger as a buzzing weight. "Yes, as ordered."

A _harrumph_ from Ratchet and he came around to face him, running a myriad of scans. "The compounds are gathering around the chamber," he announced, satisfied. To the mech's querying look, he added: "I included chemical markers to direct the deposit location of the raw materials. It's more efficient this way. Depending on how the sparklet responds to it, I may have you ingesting the mix daily to keep it saturated."

Suppressing his visceral reaction to the notion of drinking the foul concoction on a daily basis, Optimus simply nodded and waited for Ratchet to direct him. The medic was hesitating, though – obvious in the way he turned the needle around and around without really looking at it. Near it, but not at it. Finally, he flicked the tip of his pede out a little to catch Ratchet's shin, drawing his attention.

Ratchet flicked a brief, apologetic smile, before considering the needle and connected receptacle again. "The gentle approach hasn't been effective thus far, which was why I wanted to try bombarding the zygote with compounds and have you running a little hot around it to improve the charge. I'd, like to increase the charge of the budding to give it the best chance."

Optimus straightened a little as he absorbed that, immediately seeing the true undercurrent of meaning and its consequential trepidation. Budding came from an overload, and as they were keeping this 'project' strictly professional, there was no option to do it the traditional way. This left Ratchet artificially stimulating an overload through direct spark manipulation, which he'd been unconscious for when the chamber had just been installed and, weeks ago, experienced fully aware for the first time. It had felt like a sharp barb being pulled out the length of his spike, so abrupt and powerful that it hadn't been at all pleasurable in the traditional sense. There had been no warming in his systems, no swelling in his spark, just the final result forcibly dragged out of his body. To increase the charge necessitated sensory foreplay.

When Optimus didn't immediately offer a response, Ratchet sighed and set the needle next to him on the berth, folding his arms. "It would be better to keep you online, but I'll put you under if you insist. Really though, youngling, there's nothing to be embarrassed about."

"It's not that," Optimus cut in, brushing a hand over his optics. A pause as he sought the words before finally giving up, looking back to Ratchet instead. "How long do you want to build the charge?"

"At least ten minutes."

The Prime's spark made a strange little pulse at that – ten minutes, held on the absolute brink of overload and ecstasy, with a bot he could neither bury himself within or against. Perhaps it would be simpler to do things the traditional way, a sly little voice supplied from the back of his processer. Ignoring the thought, he met Ratchet's optics without reservation. "Whatever brings the best chance for a sparkling. I trust you."

Ratchet smirked good-naturedly, taking up the needle again and gesturing to the berth. "I promise not to jump your aft."

A chuckle that he knew perfectly well was in part from nervousness, the humour to dispel tension, and then Optimus swung his long legs up onto the berth, settling his shoulders back. He brought up one arm to place a fist behind his helm, thus lifting his chassis and spreading the thick plates in a way that would accept the needle. Ratchet pressed a hand against one half of his windshield and guided the needle with the other, pushing hard through the sinuous upper layers of protoform and the base of the gestation chamber. Optimus held his systems tight and still, grunting when the needle breached and then waiting in mutual silence as their already-bonded zygotes were injected inside. Ratchet emptied the syringe slowly, scanning intently to ensure that the contents were all emptied into the chamber. A zygote outside of the organ, though it wouldn't grow, would still be dangerous if it went unnoticed.

Once finished, Ratchet set the needle out of the way and came to stand alongside the Prime's chassis, one hand on a flame-patterned shoulder whilst the other warmed in preparation. Optimus's optics were steady on his, seeking assurance that Ratchet was okay with this, that he wasn't being made to feel awkward by this necessity. That his one-sided overloads looked to be coming from a bot he'd never lain with was Optimus's own issue to come to peace with.

Ratchet extended his hand though didn't make contact, giving Optimus the habitual last chance to back out. "Alright, Prime: Ready to get sparked?"

His cooling system had already cranked up a few notches, much to his chagrin, and Optimus slid his gaze to the ceiling with a sigh. "At your leisure, Doctor." Despite his tone his body stiffened, braced.

Without pause, Ratchet brought his hand to the scarred metal over the warm point of the mech's spark chamber, waiting until the body finally relaxed a little before he began to send electrical throbs out through his palm. They were gentle, more coaxing than deliberately stimulating in themselves, and he noted optical shutters closing and hydraulics sagging with a hiss in response. After thirty seconds of physically adjusting the mech to the sensation and situation, he increased the force behind his field-touching and spiralled them to caress and stoke.

Optimus's reaction was restrained, jaw tightening as his cooling vents picked up and his body shifted fractionally on the berth. Accelerating to a charge that would have an impact on the chamber below, prepared and waiting for a spark of a soul to enter, Ratchet had to exert force through his hand to keep the mech from arching.

Optimus had expected that there would be trials on the path to forging a sparkling in this way, but he'd not thought that it could be like this. His vents gasped as Ratchet dragged a line of light through his spark, _just _so, that sent a jolt across his systems and pooling in his groin. Already his interface cover was beginning to feel uncomfortably tight, but that was a boundary they simply could not breach. No matter how achingly needed it felt. To save himself, he bent a leg and pressed the fist that had been over his head into the curve of his hip.

Ratchet made no comment or indication that he'd seen the movement, tracing his fingers in a circle over the armour plates to vary the charges, undulating the 'pressure' in a slow rhythm. Optimus shifted again, then a soft sound like am organic inhalation from behind his faceplate, and finally a dam had been burst. The medic tightened his grip on the plates when large fingers moved to grasp the wrist of his assaulting hand. He placed his other hand over the gripping one, offering a comfort that felt wholly out of place in this scenario of deliberate pleasuring.

Aside from the secondary effects of the sight and sound of his Prime in a barely-controlled, near-torturous state of ecstasy, Ratchet was neutral. No pleasure fed back into his systems from the touch, the pulses he was sending purely clinical and the fields those that he used in a myriad of medical procedures. His scanners informed him that the powerful spark had already swollen and increased its output to levels he'd taken as sufficient to bud in the past, gravitating down towards the waiting chamber. In preparation, he triggered a series of injection lines to emerge from the back of his manipulating hand, mentally guiding their tips down and piercing through to the gestation chamber.

"I'm adding twice as much Mercury to act as a colloidal this time," he murmured, making the first addition to the chamber. It was professional habit of commentating these procedures with Optimus that had him speak, as he knew full well that he wasn't being heard. The zygotes settled into the bright fluid immediately, and the spark charge drew them up and against the wall of the chamber.

Ratchet smiled at this first success, accelerated by the compounds he'd had Optimus ingest in advance. The raw feeling of encouraged relief was quickly set aside in his processor when the big mech jerked, struggling to remain still on the berth. It was pleasure that was causing his body to twist, and his vents to heave as his core temperature rocketed, but it was a strange kind that would have been unethical without Optimus's consent. Indeed, consent was why Ratchet had wanted to keep him online for the budding, despite the discomfort.

A triple-beat pulse through the Prime's spark made him more difficult to keep still, and Ratchet could feel the eddies of the building charge as a whispery heat against his palm. The zygotes pressed harder against the chamber wall, drawn to the charge as the bud would be drawn to them. Another controlled ripple of current had Optimus groan despite obvious effort to keep the sound back. The trembling hand around his wrist tightened.

"Ratchet…. Please."

It had only been six minutes. The charge had to be as strong as possible. Had to have the best possible chance. "I'm sorry, Optimus - not yet." Mouth tightening at the moan the refusal garnered, Ratchet prepared the next line.

The second injection had taken a significant chunk out of their monetary budget, but General Morshower had authorized it without protest as part of Optimus's 'treatment'. He introduced it carefully, glad that even if this carriage failed the tiny fragments of Lutetium would remain reusable inside the chamber for future attempts. Comparatively massive amounts of iron and cobalt followed and completed the cocktail of injections. Finally, he cranked the voltage from his hand up, prepared for the buck.

Optimus received the distress signal before Ratchet could intercept it, optics spiralling wide with a gasp. "Bumblebee!"

Swearing under his vents, Ratchet jammed the Medbay of any other incoming signals, though the damage had already been done. The charge stuttered, began to diminish incrementally. At the same time as he opened a private channel to Ironhide outside, Ratchet switched the hand that had been restraining the mech to manipulate his spark and brought the other already-warmed hand to cover Optimus's own by his cod piece. With a startled shout Optimus twisted, his spark flaring past the point it had reached before, and Ratchet added even greater pressure to his touch.

:Ironhide, report.:

Across the comm., Ironhide's words were sharp. :Bumblebee and Sideswipe are under fire from Starscream and another 'Con. Jolt and Sunstreaker are inbound, but they're nowhere close.:

And neither were they. His attentions partitioned, Ratchet noted that the spark charge was rapidly nearing a terajoule of potential energy at the same time as his voice softened towards Ironhide. :Go – if the Decepticons send reinforcements-:

:I ain't leaving Prime,: came the snapped reply, adamant and assured. :Could be a scattered attack and 'Cons are inbound right now. You do your job and I'll do mine.:

Ratchet was cut off from even an acknowledgement of the statement by Optimus's spark reaching its absolute capacity for energy, blossoming violently into overload without any final push from him. He was absently grateful for the strength of the dampening field that swallowed the racket – doubtless Ironhide would have crashed through the reinforced wall had he heard the roar. When the long body sagged back into ripples of aftershocks, vents howling in an uphill battle to cool the overheated systems, Ratchet ran a quick scan.

Budding – strong and already attached to the chamber wall. All of the additional steps had worked. Ratchet gave a hard exhale, optics shuttering and hands gripping the edge of the berth.

It took another full minute for Optimus to regain himself, his chassis feeling like something hot was ricocheting about inside it and his extremities comparatively numb following the most overwhelming overload of his life. When he finally turned his head to the direction of the medic, forcing the short blast of a distress signal to the forefront of his mind, his optics narrowed with effort. "What's happening?"

Ratchet didn't answer immediately, helm tilted as he communicated internally before finally shaking his helm. "It's already over. Bumblebee and Sideswiped were ambushed en-route to the base, but Starscream and the other Decepticon are gone now."

There was a familiar quality in the mech's voice that made his tank twist, and Optimus forced the purely-physical after-effects of the overload aside to sit up. He stopped short of standing from the berth, privately uncertain that his legs would support him just yet. "Tell me."

Finally Ratchet met his optics, his face unreadable apart from those shadowed points of light already clouded with shocked, frustrated grief. "It's bad. Mikaela Banes has ceased to function."

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><p><em>My first time killing such a central character like this, and I was very nervous about posting it. It's very much for the plot, however, and I hope it's accepted as such.<em>

_There's a poll up on my bio about the future direction of this story, and it'd be great to have your thoughts on that. _

_As always, thank you for reading and a review, long or short, would be most welcomed. Particularly because I've been bricking it about uploading this chapter._..


	5. Chapter 5

_Some events from 'Dark of the Moon' start turning up from now on, which I suppose is a kind of spoiler though I'm not remaining loyal to the plot of the film.  
><em>

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><p>Only a Prime<p>

_Chapter 5_

Las Vegas in a blackout was unearthly, the myriad of neon strips and lights reflecting the moon's comparatively weak light and bringing the Strip a spectral quality that reminded Optimus of Cybertron in its dying hours. NEST had evacuated the civilians who hadn't run and cordoned off the zone demarked by the collapsed ruins of three massive hotels. Sideswipe stood with Ironhide on the precipice of a cavernous hole, its depth cut off by a melted plug of rock and obviously the escape-route for something massive.

Sunstreaker and Jolt were trying fruitlessly to blast through a plug, having collected the Cybertronian detritus and then decided to stay out of the way. Bumblebee sat with Ratchet in the rubble, all of his serious repairs completed. Sam was in a stationary ambulance, grey and mute. The other ambulance was already gone.

Optimus took in the smouldering craters on the still-standing buildings without bringing his scanners to bear, needing nothing more than his optics and experience to know that kind of blast pattern.

"Shockwave."

The acknowledgement was more a quiet growl than a statement, and he lifted his gaze higher to pick out the same damage on the upper storeys. It seemed that the Decepticon had turned rogue, firing on Starscream as much as the Autobots and civilians that were here. And he'd brought something with him that made Scorponok's tunnelling look like a termite on an anvil.

"I don't know what the frag did that," Ironhide began as he approached Optimus's back, motioning back to the well, "But it's not like any bot I've seen before."

"Wasn't a bot," Sideswipe broke in, skating around to face the larger mechs on wheels still hot from the battle. Whilst Bumblebee had focussed on protecting the humans through escaping, he'd moved off and fired on Starscream and Shockwave to keep their attention on him. He felt now that it had been a grave miscalculation. "That, thing was a cannibalised mess of denta and cabling. I doubt it even had a spark under all that metal."

"Then Shockwave has taken to building monsters in the indeterminate time since he arrived," Optimus concluded flatly, taking in the sections of debris that appeared to have been torn asunder and burrowed through. Nothing had been taken, and there was nothing of significance to a bot here anyway. "I doubt that this was more than an opportunistic attack – a trial run for this creature."

"That's how it looked," Sideswipe agreed, his arms stiffening at his sides as he resisted the urge to cross them. It had happened so _fast_, so violently, and the screaming… "Starscream arrived first and was fixing on Bumblebee, more trying to separate him from the children by making him transform than trying to offline him."

Optimus nodded fractionally. "Likely in an effort to ascertain the location of our new base."

"And then, just out of nowhere, out of the middle of what used to be a hotel, this thing just, erupts, and starts chewing everything up," Sideswipe went on quickly, optics brightening as he projected the short clip of the clearest footage he'd gained of the creature. It emerged into the open only once, twisting like a mass of snakes to reveal Shockwave at its core before it tore into the structures surrounding it. "Screamer looked as surprised as us, and Shockwave wasn't taking any side but his own. Once he'd chased Starscream off, he just got tangled up in his monster again and sank into the ground."

Optics shifting towards the ambulance and to Bumblebee nearby, Optimus asked the heavy question quietly: "What happened to Mikaela?"

Sideswipe glanced down at that, jaw clenched as he returned to some internal conflict under the gaze of his Commander. Ironhide folded his arms and snapped an encouraging click, forcing the younger soldier to look up again. "It was my fault, Sir. I was thrown by Shockwave's pet and too focussed on keeping Starscream back. Shockwave put out a volley from his cannon, and 'Bee just couldn't…"

Ironhide touched the lithe mech's shoulder with his knuckles to draw his attention, voice calm and assured. "I'd have focussed on Starscream as well. Higher priority target as Megatron's second, and he was obviously after the children. You did good."

It was obvious that Sideswipe was far from convinced, but Optimus hummed his agreement and touched the mech's shoulder as well before leaving the warriors alone to speak. He crossed the site with little concern for the human soldiers moving about, fully confident that they would keep out of the way of his pedes without him needing to look out for them. Ratchet stood when he came to stand before Bumblebee, looking him over before murmuring that he would be closeby.

After a silent moment, Optimus shifted and lowered himself to sit beside the scout in the rubble. His olfactory sensors highlighted the presence of human blood and other viscera within his frame, mingled with burnt energon. There was nothing he could say that would not only be a platitude, and it seemed that his proximity was providing a kind of support for Bumblebee as the mech lent gingerly against his arm.

Their fields mingled, sharing trauma and grief and support and strength, until finally the scout churred a desolate note and shuttered his optics. "I should have… gotten them away. Fled."

Though it was unseen, Optimus's helm twitched in the negative. "Then you would have left Sideswipe alone against Starscream and Shockwave, and he would be dead, and there would be no one to stop them from coming after you anyway."

He followed Bumblebee's gaze to the ambulance, where his sensors told him that the boy had been given warm fluids and been joined by Lennox. "They have known the risks of being with us since we arrived, and much as we try to protect them, they are fragile. That this could happen was always likely, but the decision was theirs."

"I felt her." The admission, quiet as it was, fell between them like a blast, and Optimus touched a gentle hand to the scout's backstrut. "I felt her break. She was wet."

Optimus gave the stiff doorwings a sidelong look, noting how deformed the passenger side one was beneath a crust of burnt dirt. "To save Sam was still to defy the odds," he consoled softly, his fingers moving fractionally over the interlocking plates that made up the mech's back armour. "And this was not your fault."

Bumblebee nodded slowly with a vacant stare directed at the ground, suddenly looking more exhausted than anything else. Optimus flared his field again and drew the mech closer to his side, his spark aching as he thought anew about how young he still was. No longer a youngling, and certainly hardened by war, but still eliciting a great swell of protectiveness in moments like this. Emotional maturity came with experience rather than time, and tonight Bumblebee had aged.

From nowhere he had the sudden urge to tell the scout of what he and Ratchet had been trying to achieve. That they were trying to make a sparkling would have brought so much hope and joy to the young mech. It would be overshadowed, of course, but for a moment it would banish this haunted look that seemed so wrong on Bumblebee's frame. Ignoring how it looked, Optimus put his arm fully around the mech's waist and allowed him to curl against his chest plate, dried blood flaking away as he shifted. Instinctually, the Prime warmed his surface plates to a comforting temperature where Bumblebee's body met them.

:You're going to be a model sire,: Ratchet privately from where he knelt by the ambulance, murmuring to Sam whom had come to sit on the edge of the doorway. :Not that I believed otherwise, anyway, but it seems like some progenitor instincts are already close to the surface.:

:I would do this whether or not I might be carrying,: Optimus replied, though not defensively. He looked to watch Ratchet in profile, where it appeared that the medic's attention was wholly fixated on Sam.

A short, dry chuckle came back across the comm.. :You're definitely sparked, Optimus. The drive raised the charge and strengthened the bonds between the chamber wall and the zygotes as I'd hoped. It's likely I'll have to remove some before it gets crowded in there.:

One life ends, and another… Optimus brushed his free hand over his mask and across his optics, running a short internal scan. His own sensory awareness of the chamber was almost nothing, the only clues he could decipher coming from his existing systems as they were affected from their connection to it. He had come to rely on Ratchet's vastly superior diagnostic sensors and scanners for information about what was happening inside his chassis.

After long minutes spent in silence, Ratchet pinged Bumblebee into their comm. frequency and looked across from where Sam was sat by his hand. :She died instantly, Bumblebee. She wouldn't have felt much pain.:

Bumblebee straightened a little, though didn't pull away from the comforting mass against his side. Dealing with the death of a loved one, notwithstanding of how long they had been known, had become habitual over the centuries. It would never get any easier, knew, but he'd experienced enough loss to know that these bleak feelings now would become bearable and pass in time. He'd never experienced a death _from within_, though, and never had a charge even younger than himself to comfort in the aftermath.

:I don't know what to say to him,: he finally admitted, optics on Sam in the doorway of the ambulance. Lennox was sat next to the teen much as Optimus was sat with him, one hand resting on the back of his dirty t-shirt. :There just aren't the words…:

:I know,: Optimus replied with a sigh, wishing again that the humans could feel the flares and flickers of the energies that were just as integral to their language as stance and gesture. :But it is a raw wound, and will be for some time. He will endure just as you will.:

Ratchet pinged him to another channel on an encrypted tier, well outside of Bumblebee's awareness. Physically, he extended a cleanser hose from his side to remove the organic remains from the scout's body, having failed twice already to clean him because of the distress it brought about. Prime's solid presence kept the scout silent after an initial flinch, optics shuttering as he worked quickly to dissolve away the matter.

:Optimus, much as I dislike interfering when you're doing another spark some good, I think it's time to focus on your own. As you know, the first twenty hours after budding are crucial, and because the increased charge has already strengthened the sparklet, I want you to keep it up until this precarious stage has passed,: he advised evenly, imbuing his tone with more confidence than he felt. They were figuring this thing out as they went along, but this time they seemed to have struck upon the right path, and he was going to see it pursued ruthlessly.

Torn, it took Optimus a minute to make the decision to leave before he began to gently move away from Bumblebee's frame. He sent a pulse of reassurance and regret, the same mix he'd left with many soldiers in his command when he had to leave the front line after the battle was over. When he could he was last off the field, but he had to serve his soldiers in more ways than they served him – most of it through paperwork and meetings.

:What do you suggest, Doctor?:

Nudging Bumblebee to turn for him and expose his stained doorwing, Ratchet didn't look up to respond. :There's nothing more than cleanup we can do here, and the sooner we regroup inside the Hoover Base the better. Go back to Diego Garcia for that trailer and haul it back – should be all the strain on your systems the chamber needs for the charge.:

:Ironhide will come.: It was a statement of the weapons specialist's will, not of Optimus's desire to be escorted. He was content to drive back alone and leave Ironhide in charge of the convoy.

Ratchet grunted both to the statement and to indicate Bumblebee to flare his back armour, revealing his marred interior. :The Twins will suffice to get us there safely, and with this 'Frankenstein's monster' about, I absolutely will not have you unsupervised out in the open. Now get. I'll watch over Bumblebee.:

Optimus smiled fractionally behind the faceplate, optics bright. :Now who's being an overprotective sire?:

:My aft,: Ratchet snapped back with an irritable glance, though the feeling wasn't truly in his optics. :I'd be telling you the same thing if you weren't sparked up.:

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><p><em>Feedback, as always, is greatly appreciated. I'd like to think that I'd write even if I never got reviewed, but honestly it's a great motivator to keep going.<em>

_Thanks for reading!_


	6. Chapter 6

_Starting to introduce some more subplots into this beast, now. _

_Temporal jumps in this fic are going to be pretty standard, but I'll do my best to make them clear.  
><em>

_Keelywolfe's 'Experiments in Human Nature' has been a great source of inspriation for this fic in particular, as will likely be obvious in this chapter, and I highly recommend it if you haven't read it already._

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><p><span>Only a Prime<span>

_Chapter Six_

- 5 months later –

Of all the things Sam had expected to find in a specially-designed alien base hidden inside the Hoover dam, a basketball court was somewhere near the bottom. He'd smelt chlorine whilst in the locker room, and assumed that there was a swimming pool tucked away somewhere as well. What had turned into a short visit had turned into a day-long affair when he'd taken up Bumblebee's offer to take him home after his patrol shift. It wasn't as if there was much he wanted to go home to, he'd reasoned, and now he was killing the last hour practicing his shooting. He spent a lot of his time with Bumblebee now, both of them distracting themselves from that which bonded them but hadn't truly been spoken about. The yellow mech had turned into a comfort as much as a friend, and he ached like something was missing when the scout wasn't around. Something else he wasn't going to volunteer that they talk about.

With the reverberated echoes from the ball striking the ground, Sam didn't hear his name until the speaker was standing a few feet away. Recognizing Optimus's holoform, a shrunken version of his bipedal mode, he decided that he wouldn't have heard him approaching in any case. Though sophisticated, the projections were still only that, and made no true sound in the world that wasn't generated by the bot using it.

"Hey," he greeted with habituated brightness, wholly put on. If even half the time Sam answered in a tone concurrent with his mood, he knew he'd be bombarded with even more pity and questions about his wellbeing. To the miniaturised Prime who now stood only a foot taller than him, he gestured back towards the locker room and the base beyond. "'Bee's taking me back when he finishes patrol. I hope you don't mind."

Optimus's hologram raised a hand with a soft smile at the near-apologetic tone, optics narrowing in the corners. Privately, he still felt responsible for the boy. Had done since landing on this planet, when fate had seen fit to involve the humans in their war. "You're welcome here, Sam, as always," he assured, not iterating that it was the least they could do. That the memory of Bumblebee sitting in the rubble whilst Sam was in the ambulance was still close, and that he wished he could do more.

Sam observed the silence stretching out between them more than he participated, sensing a communication between them that he couldn't put into words and Optimus seemed reticent to vocalise. Knew that it was about Mikaela, and that it was the same non-conversation they'd had countless times before. Optimus had apologised to him after he got released from the hospital, counselled him in that steady way that made him seem even larger than the mech actually was. It had been too little, too soon, small words from the wrong person – he wasn't sure. He'd accepted what Optimus had said to him as truth, but it was only really Bumblebee that he believed – whose words could ease the sick knot that had moved into his chest.

Swallowing loudly, Sam shook his head a little to disengage himself from that train of thought for now. He spun the ball between his palms, smelling the rubber and feeling the rough-smooth texture anew. "So. Basketball, huh?"

Optimus saw the non-sequester for what it was and turned fractionally to indulge it, looking over the court. "We wished for our human companions to feel welcomed here. Sideswipe and Sunstreaker have also recently developed something close to an obsession with the game and wish to see NEST play."

Sam grinned at that, imagining the Twins goading on such a match. "Humans against bots?"

A rueful smile and Optimus passed the fingers of his right hand through the palm of his left, watching how the light distorted. "Our holoforms aren't solid enough for that."

"Yeah," Sam replied quickly, feeling heat rise up his neck. The memory of Bumblebee's holoform, the only one of the Autobots crafted to appear human, sat next to him in the Camero came unbidden. A hand just larger than his own, bright with an artificial glow, passing over the space above his wrist in his lap, offering comfort. Hovering because they couldn't touch. "Right, of course."

Optimus cocked his head slightly, scrutinizing the young man with a pang in his spark. He knew that the feeling wasn't one he couldn't attribute to the sparkling. "Are you alright, Sam?"

Sam didn't answer immediately, smiling a little to meet his optics. Biting the inside of his cheek, he thrust the ball down to the green floor and caught it on the bounce, listening to the sound echo about the large gymnasium. "Yeah. Just, you know. She'd have loved this."

A soft sound, barely more than a sigh, and Optimus unconsciously folded his arms across his chassis. The sparkling was still so small as to barely fill the gestation chamber, let alone distort it, and a good eighteen months by Ratchet's estimates from emerging. He could not feel it in the chamber nor scan for it easily within his systems, yet whenever his thoughts turned to Mikaela he became aware of the point in his chassis as if it had clenched. The juxtaposition of events would never sit easily in his spark.

"I agree," he uttered at last. "I'm sorry that we failed to protect her."

Sam's shoulder's dropped, and it was a conscious thought to hold the mech's gaze. To prove that he meant it. "I don't blame you." Optimus was silent, waiting patiently for him to go on with this opportunity between them, but Sam brushed a hand through his hair instead, the ball resting against his hip. "I've been thinking about what you said. About living here."

The offer had been made quite soon after Mikaela's death in what Optimus now saw was an overly emotional reaction on his part – a need to gather their family close for safety. It was meant sincerely, and he stood by it, but he suspected now that the carrying actinics and arrhythmic charges subtly influencing his systems he been behind it.

Ultimately, his response was even and assured. "It would afford you far greater safety now that Megatron has apparently turned to interrogation to discover the location of this facility."

"I get that, I do, and God knows my folks are all for it," Sam replied, rolling his eyes a little. Part of the reason he was spending so much time with his guardian at the base was because it was the one place his parents weren't constantly phoning to check up on him. Their protectiveness felt like them trying to force him back into a mould that better fit the 'baby booties' he knew were still on their dresser.

The Autobots, by contrast, had always treated him like an adult – even though he still felt like a pretty useless one. "But won't I just get in the way? I mean, I'm no a soldier or a mechanic or anything. I'm just some kid who got lucky finding an alien robot instead of a used car."

Optimus's hand twitched from where it rested in allusion against the armour of his bicep, obviously meaning to touch his shoulder. "You are a bright young man whom has been deemed of importance by fate on more than one occasion, and could not 'get in the way', as you put it." His facial plates slid into a wry smile, optics bright with mirth. "If you wish to work whilst living here, I assure you than I can find a _great_ many things that you could do to help us."

Breathing a laugh at the almost-threat, Sam rubbed the back of his neck again. Optimus carried himself with such humble nobility and dignity that to actually see him poke fun was a treat. Since Egypt and learning about the Prime line, Sam had decided in his gut that the Autobots would walk into their equivalent of Hell for Optimus. All the qualities of a Prime were admirable but could so easily be abused – as they had been by the Fallen. He knew, from the heavy sadness that so often shadowed his voice, that Optimus struggled with that burden at times. It was that humility that had sealed his respect for the ancient mech. It was easy to lead with the power of birthright; it was something else to still be working to deserve it after untold centuries, and to continue to earn the unquestioning loyalty of the Autobots.

"Okay. I'll talk to my folks about it, but I think, yeah, I'd like that. Thanks."

Optimus made a soft sound, genuinely pleased and a little relieved to hear that. "Thank you."

Unsure of how to go on from this strange little moment, Sam bounced the ball on the floor again before passing it lazily between his hands. It was a nervous habit he'd picked up to shift something from one hand to the other. He'd seen a few of the bots handle things too fragile for their powerful frames with short-range energy fields, the object floating back and forth between their palms as if being toyed with.

"So, uh, how's the treatment going with Ratchet?"

Optimus's hologram appeared to shift its weight across his pedes, a behavioural tell that Sam had recently become wise to. "Quite well, I feel," he replied, the fingers of one hand curling in a brief flex over the centre of his chassis. His optics narrowed fractionally before he went on, and his tone hard turned cautious. "Though of course there is no guarantee that this attempt will work any better than the last have."

"But you're okay though, right?" Realising just how much he sounded like his parents, Sam went on quickly: "I mean, we're not going to have to go breaking into thousand-year-old tombs again?" The lilt of humour in his tone was jarringly forced, and made the concern in the words even more obvious.

Optimus raised a blue hand chipped and scratched with silver scars from his chest, calming off the train of thought. Difficult as it was for him to continue the pretence that his life was in danger if Ratchet didn't manage his mystery condition, he knew that the concern for his wellbeing would increase tenfold if everyone knew the truth. There were still a few months left before anything less than a detailed scan would be able to detect the sparkling, and he intended to keep the inevitable over-protectiveness at bay for as long as possible. More than that, he didn't want to grieve the Autobots if this attempt failed as the previous two had done. It was also safer for the knowledge to remain between himself and his medic, rather than allowing Megatron the opportunity to plot for his coming vulnerability.

"I'm well. Ratchet is taking good care of me."

The ball ceased its back and forth motions, now held firmly between Sam's hands. He glanced to the Cybertronian-sized door as if expecting to see Optimus's fully-sized form stood against it. "Where's you're, um, body?"

"Just leaving my office," Optimus replied with a nod in the direction of that section of the base. "Ratchet has requested me."

Though there was nothing arresting in the Prime's tone, Sam always felt his chest tighten a little whenever Optimus mentioned seeing Ratchet. "Is everything okay?"

"I don't believe it's urgent. Though I would like to focus my attention," he added with a subtle apology, adjusting his arms to bring them casually against his sides.

Though impressive and useful, the split-processor thing was still a little unsettling to Sam. It was strange to think that as he was standing here talking to Optimus, with the mech's attention apparently on him, he was also concentrating on moving about and working elsewhere. "Sure. I think Bumblebee's finished his patrol by now, so I'll be out of here soon."

Something flickered across the Prime's optics, visible only because they were standing so close, but he betrayed nothing else. "It is good to see you again, Sam."

"Yeah, you too, Optimus," Sam replied, watching the hologram suddenly cease to be and leaving him alone in the suddenly-larger gymnasium.

* * *

><p>Bumblebee had requested this meeting before he'd left for patrol, responded to multiple queries during his drive with Jolt around the main roads, and now sat on a berth waiting patiently for Ratchet to appear. He hadn't had the opportunity to really take in the new Medbay since helping to move all the equipment into it, and now explored it with detailed scans.<p>

After the humans had finally made a definite decision about them staying on Earth as refugees and comrades, they appeared to have given them full support in setting up the Hoover Base, particularly in terms of materials. There was still a lot of work left to be done but the place was already feeling more like the Ark than any human structure ever had. He hummed an impressed sound at just how much of the equipment they'd had on the ship had been rebuilt in here from scratch. Most of it would just make Ratchet's job easier, but some of it could have saved the lives of Auotbots lost on this planet.

Ratchet emerged from his office without ceremony, coming to stand in front of the scout with folded arms. His expression was unreadable, devoid of any of the interest that Bumblebee had been anticipating. Suddenly uncomfortable, he made to slide down from the berth to have this conversation more formally, but the medic kept him on the berth with a short sound and raised hand.

"No, stay right there. Prime will be here shortly."

Optical ridges twitched downwards at the curt tone, and Bumblebee felt a sudden pang of confused anxiety. "Prime? But-"

Punctual as ever, Optimus stepped through the heavy doors before the mechanical rollers had finished opening them. Bumblebee felt a burst of comm. signals in the air, and his frown deepened.

Though the battle mask was up, the arrangement of plates around the tall mech's optics revealed that his expression was neutral. A complete contrast to the medic's. "Is everything alright, Ratchet?" he asked as he came to stand at the end of the berth, angled to face them both.

His own features still stony, Ratchet nodded towards the scout. "Bumblebee has requested the codes to modify his holo-emitter."

Optimus's expression remained schooled as he glanced to Ratchet, though he conveyed his thoughts clearly enough through that gesture. They could all change the appearance of their holoforms with little effort, but to alter the parameters of the emitter itself was more significant. There was no official requirement for him to need to be aware of this, and no reason for Ratchet to resist a mech as experienced with programming as Bumblebee with such access. When the medic offered nothing, he met the younger optics now edged with trepidation, his tone light. "What kind of changes do you wish to make?"

Bumblebee glanced between them both before he answered the Prime directly. "It's possible that our holo-emitters can be adapted to form a more complex electromagnetic matrix, and control a great enough density of ionized molecules that the projection would be solid." It was a concise and dry explanation, as if he'd delivered an incidentless patrol report as opposed to proposing something that could change everything about their interactions with the humans.

"I see," Optimus murmured. Immediately he could see where this was going and why Ratchet was concerned, though he kept his focus on the scout. "And what applications do you anticipate as a result of this?"

"Improved interaction with our human allies, largely," Bumblebee replied crisply, shifting as he sensed the bite in Ratchet's field. It wasn't difficult to guess at what the other mech was thinking, but this was not about being able to touch Sam. Not entirely, some distant part of his processor chimed in. He flashed a smile as he forced the treacherous little thought away. "And it'd be useful to hold a pen when NEST are doing inventory."

"And you'll be wanting to sync sensors up with the emitters as well, I've no doubt," Ratchet drawled, shoulders tightening with obvious disapproval.

That hadn't been part of his proposal, though it was a definite intention. Bumblebee straightened a little. "It would make it far easier to interact with the environment if we could feel through our holoforms."

There was silence as they both waited for a ruling. After a moment's consideration Optimus nodded fractionally, though with finality. "This sounds as if it could be very beneficial to the Autobots. Carry on, though I would advise that you do so with caution. The holographic arrays can be complicated at the best of times."

Unable to suppress a smile, Bumblebee hopped down from the berth. Ratchet silently sent him the required codes a moment later, along with an excessively detailed document on how not to muck up the rest of his systems whilst making superficial modifications. "Yes Sir. I'll keep you updated on my progress."

Ratchet waited until the scout was outside and the heavy doors had slid closed again before turning to Optimus. "To hold a pen, my aft. This is about the boy," he fairly spat, optics narrowed.

"Yes," Optimus conceded softly, his stance remaining passive despite how Ratchet's hand moved to rest on the berth in a fist. "But I also know that this is the first time that I have seen Bumblebee excited about something since Shockwave's attack."

Ratchet's optics flickered as his processor automatically leapt back to that scene. He still wasn't sure if he'd imagined them, or whether the mingled digital and human screams he'd found in Bumblebee's processor were real.

"No matter how positively this 'project' will appear to affect his mood, the truth is that it's unhealthy," Ratchet pressed, jaw tightening. "You know as well as I do that he and Samuel have been threatening to advance beyond friendship since Mikaela's death, and it's all out of Bumblebee's guilt."

Optimus sighed a little, folding his arms. He had seen this possibility coming for some time, and had long been considering the ramifications. Their numbers were few and they had already overcome many of the species-divide barriers with the humans. It had been prudent to anticipate the impact of curiosity, if not genuine desire, between both their kind. "You know my feelings towards the rights of sentient beings, and love is an integral part of freedom. I cannot say that I am unconcerned, but Sam is wiser than his years and I trust Bumblebee to be careful."

Something in Ratchet's engine growled, and he lashed a dismissive hand. "I would trust Bumblebee if he hadn't experienced the trauma of feeling responsible for Mikaela's death. He's the only bot I know except for myself who has had somebody die inside of them."

Ratchet caught his words as soon as he'd said them, optics wide and body freezing. Immediately he softened, chagrined. "I'm sorry, Optimus – that's not what I meant."

As unintentional as the words had been, they still stung, but Optimus touched a hand to the medic's shoulder. "I know, old friend, and there's no need to apologise," he uttered softly, drawing his hand back to himself. "I will speak to them at a later date. For now, however, Bumblebee needs this distraction and Sam needs his guardian. In what capacity, I do not yet know, but we will be vigilant in seeing that it is not harmful to either of them."

Ratchet accepted the verdict with a wearied sigh, tempering his alarmed concern for the younglings for the time being. Then, never one to waste an opportunity when a bot was in the Medbay, he motioned for Optimus to sit up on the berth. His hands were gentle as he felt around the wide chassis, scanning through his fingertips. A part of him knew that direct contact like this wasn't necessary for the scans when there was no interference, but there were times when it had been right to touch, and he'd become too used to it. "How have you been feeling? Any pain?"

"I'm well," Optimus replied as he watched the sharp beams of light play between his parts, over the gestation chamber. It was times like this when he envied Ratchet's superior sensor array, though the medic always passed on a summary of the results when he was done. "And there's been no discomfort. The power fluctuations have settled."

The medic hummed a flat sound of satisfaction, ending the scans a few seconds later. One hand lingered on the mech's plates longer than it needed to. Protective. "That's good, though I would still advise that we don't get our hopes up," he uttered evenly, his tone neither dismissive nor concerned. From the beginning they'd both had to be realistic about the high risk of failure, and with two miscarriages already behind them, Ratchet would not allow them to be lulled into a false sense of security just because this carriage had lasted so long.

When Ratchet met Optimus's optics, he refocused his own in surprise. Though subtle, there was definitely a warm smile pulling at the edges of his mouth. "What?"

Optimus cocked his head a little, his hands resting in his lap. "That's the first time that you've said 'our'," he replied simply, softly.

Ratchet's armour bristled a little, and he shrugged one shoulder to make his reply seem an offhand remark. "Well, it is ours."

An optical ridge arched at that, and now Optimus smiled outright. "Beginning to come around to the idea of being a sire?"

"Hardly," Ratchet replied dryly, moving from the berth to one of the storage cabinets and retrieving a cube of compound-rich energon. He was using it as a weekly supplement, and though he knew he didn't need to, he still supervised it being ingested because of its appalling taste. "The whole base will be raising this sparkling."

Optimus took the cube without comment, steeling his olifactory sensors before drinking the pungent sludge in one draw. He still hadn't been able to work out which of the many ingredients it was that made the viscous fluid so foul. Handing the empty container back, he cycled a deep vent as he felt the mix settle heavily in his tank.

Building a new Cybertonian internally had been a taxing process for femmes on Cybertron, but still an alternative to taking a sparkling frame to the All Spark that many had chosen. It was more intimate, and gave a period of almost an Earth year for the sparkling to be anticipated, bonded with in its gestation, and prepared for by both its creator and sire. Here, without many of the materials a carriage needed available for ingestion, the sparkling was leeching directly from its carrier's frame and leaving the older structure to regenerate the missing mass. It meant a longer, more inefficient carriage even without the complication of it being a Prime spark being borne.

Such obstacles were rarely far from Optimus's processor as the carriage slowly progressed. "Is there anything more I should be doing?"

"Not as yet. Just, keep making sure you're getting full recharge cycles, doing enough to keep your systems warm, and ensuring that your energon levels stay high. Beyond that…" Ratchet made a vague, helpless gesture with one hand. Much as they tried, there would always be limits to what they could do, and the outcome would always be up to Primus rather than them.

It was the answer he'd expected. "Understood." Ratchet released him with a nod, already moving towards his workbench to retrieve one of the myriad of parts to work on. Sliding down from the edge of the berth, Optimus paused mid-stride as a thought struck. "Ratchet?"

The medic looked back from the energon splitter he had just begun to examine. "Yes?"

"These new holoforms," he began, optics bright with thought. "Would using one draw upon more significant levels of spark energy?"

"You mean to keep up the charge?" Ratchet asked, optical ridges flicking upwards.

For the last five months he'd been content with Optimus taking a long drive in the early morning and evening to exert his systems enough to deliver and replace mass quicker. It seemed to be helping the carriage, but the demand of time had already become a nuisance between NEST's superiors and the Prime's day-to-day duties. Their holoforms as they were now didn't take a lot of energy to run, though they did allow two disparate things to be done at once. Perhaps their usefulness could be expanded further, Ratchet reflected.

"Well, if what Bumblebee is designing for integrating tactile sensors as well as solidity works, then it'll draw more significantly from a bot's spark to power it than the current projections do. Using it continuously could have its advantages."

Optimus hummed a thoughtful sound, his optics drawn to the closed doors that Bumblebee had passed through just minutes ago. "Then it appears that Sam's fate is still affecting our own."

* * *

><p><em>As always, thanks for reading! <em>


	7. Chapter 7

Only a Prime

_Chapter Seven_

* * *

><p>1 month later<p>

* * *

><p>The meeting space in Diego Garcia had been built quickly to meet minimum requirements – a metal frame with room for the Autobot leader to stand between the three sides for conference. In the Hoover base, the formal meeting room had been built by the Cybertronians for Cybertronians. It was a theme repeated throughout the underground facility, sincerely welcomed by the long-nomadic and displaced race. Everyone had contributed to modifying the new base, making the most of the permission they'd been granted to make it a comfortable living space as well as a military focal point.<p>

A long, thick steel table was surrounded by five equally sturdy chairs, and against the back wall an observation platform of sorts had been rigged for NEST personnel. Built from parts of fallen Decepticons, the monitoring and communication equipment ran silently.

It was only Ironhide, Sideswipe and Lennox in attendance this morning, at the weapons specialist's recommendation. Within seconds of arriving, Optimus had understood why. His optics were fixed on the blackened and crinkled cylinder on the table, the length of his arm and clearly torn out from a longer strand.

"Cybertronium."

Lennox had foregone the observation platform for this small gathering, standing atop the table to complete the square. He folded his arms, expression drawn. Ironhide had filled him in on the significance of this discovery on the way back, and he'd yielded to his guardian's request not to allow anyone – including his own men, to know of it yet.

Ironhide had been the first to sit having sensed upon entering the Prime's sickly field and low on energon readings. Sideswipe, and thusly the tall mech, had followed suit. To Optimus' right, he set his fist and forearm on the table with a rumble. "A synthetic form of it, but that's right."

"That vein was a hundred and ten feet beneath the Main Strip," Sideswipe expanded, his own arms folded and tight to his chassis. "No telling how long it was for sure – the tunnel went on and on. Scanners went eighty-four miles before it splintered."

"Then at least we know the purpose of Shockwave's tunnelling machine," Optimus concluded, picking up the fragment of an undoubtedly massive network. The minor alerts flashing up from his disgruntled systems were invisible in light of this development.

He'd sent them to scout the site of Mikaela's death in the early hours when the Strip would be quietest. Bumblebee would have been the logical and procedural choice, but Optimus could not in good conscience order the young mech back to Vegas.

Shockwave's presence there had nagged at his processor since leaving the city. It was impossible to write off the incident as random destruction by that particular mech. The Decepticon scientist did nothing – waste no physical or mental energy, unless logically and tactically justifiable. Now at least they knew what he was doing, but Starscream and Barricade's behaviour suggested that they weren't working with him.

Troubling.

Optimus set the item back down. "The tunneller must also be laying this fabrication behind it as it progresses. Power conduits, a field-free communications array…"

"It's alive, Optimus," Ironhide uttered, watching the Prime intently. He catalogued every minute response, filing away ever nuance and contradicting emotion. "And it's growing on its own along the tunnels that have been made for it. And I reckon they cover the state by now. Maybe even the continent."

"Shockwave's growing a new Cybertron beneath our pedes." Sideswipe thumbed over the covers for his blades, otherwise still. "Few years, once it's stabilized, it'll displace everything the planet has on its crust."

Unseen but doubtlessly detected by the sensitively tuned mechs, Lennox closed his eyes with a controlled exhale. He and a small NEST squad had accompanied the two mechs to co-ordinate with the local authorities and cordon off the streets, but it had been a quiet follow-up mission. A small note in the Major's paperwork.

Not so small, apparently.

When he looked back up, Optimus had fixed him with bright optics conveying both sadness and genuine sympathy, and he straightened with a nod. What they were dealing with was alien to him, and Lennox had more than enough faith in the Prime and his team to defer when he was out of his depth.

Optimus placed the Cybteronium back onto the table in front of him, seeming to collect his thoughts for a moment before speaking. "For the time being, and until we have further investigated and confirmed the possible magnitude of this development, this is confidential. Within the Autobots, restricted to ourselves and Ratchet."

Ironhide grunted his agreement whilst Sideswipe only gave a slight nod. The Prime looked to Lennox. "This little information will only unduly alarm the majority of your superiors. We will disclose everything when we possess some of the answers to the questions they will undoubtedly ask."

"Alright, Optimus," Lennox agreed, taking a step forward to underline his words as he went on: "But this is priority, now. I want to sit on something potentially world-ending for as little time as possible."

"I am in full agreement, Major, and our ultimate aim will be to find a way to neutralise and remove the Cybteronium." Optimus stood to dismiss the mechs, and Lennox moved towards Ironhide to be let down out of courtesy. "I will investigate the site myself. The living material may stir something within the Matrix and shed light on Shockwave's plans."

"And the drive will do you good," Ironhide added, his tone that particular mix of a vocalised musing and an order that only came from a lifetime training soldiers. "Either me or 'Sides will escort you for backup." At Optimus' nod, he left with Lennox and Sideswipe, not needing to look to know that the Prime was pressing between his optics.

Optimus sat again, heavier than before, and shuttered his optics for a moment. Practically he knew that he should try to refuel again, now, but viscerally he knew that the energon wouldn't stay put in his tank for long. His levels weren't at a dangerous low, however, just as the complaints in his systems didn't warrant any concern.

All of the Autobots and most of the NEST staff knew that the tall mech was undergoing long-term treatment – though only a small selection knew the specifics of the lie. There was no trace of the truth – still only Optimus and Ratchet knew of the sparkling. Everyone was concerned, and though the Prime was appreciative of the concern, he was growing increasingly frustrated with being treated as if he might collapse from his mystery affliction at any moment. And he wholly agreed with Ratchet that when the sparkling was substantial enough to be publically detectable, such behaviour would increase tenfold.

A requesting ping from said medic brought him out of his reprieve, and Optimus sent a glyphed acknowledgement and that he was on his way back in return. Knowing better than to subspace a material that was not fully understood, he locked the Cybertronium into a compartment in his shoulder and began to make his way to the Medbay.

Optimus knew that Bumblebee had been successful as soon as he stepped into the Medbay, expecting Ratchet to be alone and this summons to be about the sparkling, but instead finding both mech's backs to him as they fixed their attention around the end of a single berth. They were so occupied that they didn't notice him beyond an automatic ping from their battle systems, unconsciously content that the entering figure was no threat. Ratchet's deep-scan sensors were strobing unreservedly from his optics, recording every inflection of energy and data.

Coming to stand alongside them, Optimus watched the spectacle of Sam roughhousing with what he recognized as Bumblebee's human-holoform – an exercise that seemed to have devolved from a demonstration of the holo's solidity. There was no sign of the weight in the young man's shoulders that had come after Mikaela's sudden death, and he appeared as vibrant and lively as he had when they'd first met six years ago. It had also been a long time since he'd felt Bumblebee this happy.

"I see that you've been successful in enhancing your holographic array, Bumblebee," he murmured, smiling behind the faceplate at the waves of delight radiating from the scout's field as clearly as it was written on his human counterpoint's face.

Bumblebee withdrew from Sam immediately, standing tall and straight as he brought his too-bring eyes up to Optimus. From this tiny form, looking at the Autobot Commander was like looping upon Primus himself. Tower and regal.

"Yes, Sir. Once I cracked the matrix formatting, the modification was pretty straightforward," the hologram replied, looking to his true form to mark the switch in speaker. The mech held out a small mass of metal that appeared a cross between an oversized microchip and a tangle of iron wool. "It's self-integrating if you'd like to try it."

"It's safe – I've already tested it and installed one within myself," Ratchet added as Optimus accepted the new hardware. "It auto-installs beneath the axial optic node, immediately beneath the existing array."

Optimus took it between thumb and forefinger and touched it to a receded panel by his left optic, transforming the part in. "How did you solve the problem of accounting for pressure?"

Bumblebee's holo smiled and accepted Sam's wallet as it was wordlessly offered to him. Taking it between both hands he began to twist and pull at the joined halves, manipulating the leather without damaging it. It would have taken no effort to tear it in two. "I've linked it in to our sensor net. These new holos can feel like we do, transmitting pressure, temperature and texture directly in real-time."

::To hold a pen, my aft.:: Outwardly Ratchet was expressionless, blankly scanning Optimus's helm.

The larger mech silently held a hand out to Bumblebee's holo, feeling for himself the warm hands that squeezed his fingertip with astounding solidity. ::I don't believe it's your aft that Bumblebee is interested in, old friend.::

An irritated growl across the comm. line. ::Exactly my point.::

"Bumblebee, would you take Sam to the fitness suite to diversely test the new array?" Optimus asked, not wishing for an audience whilst he tested his own holo. More than that, however, he and Ratchet appeared to need to have a talk about this development. "Submit a full report to me this evening."

"Will do, Prime," the yellow mech replied smartly, taking Sam in his hands in the same instant that his holo winked out. "Thanks for your help, Ratchet."

They waited in comm. and vocaliser silence until the Medbay doors sealed shut behind the pair, and then Optimus turned to Ratchet with a frown. "You seem significantly perturbed by the prospect of a relationship between Bumblebee and Sam. I know you're not opposed to interspecies involvements, generally…"

Ratchet huffed irritably, moving around to the other side of the berth. "Of course not. I'm too old to be any kind of prude when it comes to what others choose to 'face." A spray of cleanser from a nozzle and hose coiled beneath the berth, and he quickly ragged down the surface from the morning's maintenance. "How's the holoform coming?"

"I've just begun initializing the software," Optimus replied smoothly, watching the medic's quick and assured hands. He looked up when the patch was integrated and the contents disclosed. "Primus – there's _anatomy_ in this construct. Automated heartbeat, blood pressure, body heat…"

"Yes, a hyper-realistic layering of organs, flesh and nerves." Ratchet's remark was desert-dry. "Entirely superfluous, and gratuitously indulgent."

Optimus touched a hand to the space between his optics, sighing through his vents. "And your problem with it is?"

The medic rested his hands on the edge of the berth, voice softening. "It is not _that_ they're engaging in a relationship at all – with the detailing on these new holos, I'm certain that they'll greatly enjoy it. Rather, it is the instigation of it all that concerns me." He met the taller mech's gaze with dimmed optics, tight with feeling. "Neither of them are experienced enough emotionally or psychologically to deal with the difficulties of a relationship started by a death. Mikeala's death, the circumstances behind it and the sheer trauma… They're only going to get hurt."

Optimus smiled faintly, though with little humour. "I recall you said much the same thing to Ironhide and myself after Elita's passing, and even then you could hardly call either of us too young."

"Yes," Ratchet drawled, a single optic ridge arching up. "But you two weren't really looking to commit to one another."

The teller mech mirrored the other's expression. "We still ignored your warning, and were both fine for it. We knew ourselves, and each other, well enough for that."

Ratchet made a noncommittal sound by way of a reply, flashing his palms to signal yielding. It was enough to satisfy the Prime, however, who had already suspected that the medic's opinion on the matter were rooted in concern rather than disapproval. Truthfully, he had a similar worry, but a part of youth was learning certain things the hard way, and he sensed that both Bumblebee and Sam were mature enough to embark on this journey.

A notification alert pinged in his processor, and Optimus straightened. "The new holo is ready."

Folding his arms, Ratchet nodded to the berth between them. "Let's see it, then."

It took several seconds for the holo to appear, the projection of multiple lattices that gave it layers and staggering realism complicated to initialise for the first time. When it finally materialised, the thoroughness of the program's ability to translate Cybertronian self-image into a human equivalency was well demonstrated.

The eyes, blue and unnaturally bright, were identical to the ones on Bumblebee's holoform, their beauty a sharp contrast with the two broad, faded scars that ran through both lips and down beneath the curve of a slender jaw. Short auburn hair, long legs and a lean, muscular physique were well framed by the NEST off-duty black t-shirt and slacks that Optimus defaulted for. Overall, the holoform appeared middle-aged, battle-worn and inescapably female.

"Hn." Ratchet folded his arms, helm tipping fractionally to the right. "It appears I did a far better job on your gestation chamber than I'd thought."

Optimus shifted his weight, frowning down at the holoform as he simultaneously looked back up at himself through the partition. That the software had generated a counterpart of the opposite gender wasn't an issue to him – one of the defining facets that made femmes different from mechs had been altered, so it wasn't surprising that the programming had taken it this heavily into account. Rather, it was the soft swell between his new hip bones that troubled him.

Moving his primary focus into the hologram, Optimus lifted the cotton shirt and ran one hand experimentally over the warm skin of his stomach. It was a subtle bump, and that the sparkling had its own avatar curled inside – one that he could _feel_ in this form, drew a smile that couldn't be tempered by his ongoing anxiety for discretion. Running a hand through his fringe to brush it out of his eyes as much as to feel the hair, he looked up to Ratchet. "Can I change it into something less… incriminating?"

"I wouldn't advise it," Ratchet uttered slowly, activating his own holoform on the berth. An older man with long, silver hair and features as grizzled as his countenance knelt before the woman on the berth, bringing both hands to the pregnant swell to perform a tactile inspection. "Given how Bumblebee has programmed these avatars, it's crucial that these integrated holograms feel a natural extension of your self. To force an avatar not conducive with the human representation of your mind and spark would be deeply uncomfortable, and it goes without saying how important your physical state is as of late.

"Will it alter as the carriage progresses?" Optimus asked, and realized then that the holoform's vocal chords automatically raised the pitch of his voice into a feminine antithesis.

"My scanners are detecting a foetus, so I would assume that your humanoid self will appear more obviously pregnant as time passes, yes." Ratchet turned the female holo whilst still on his knees, cupping one hand firmly into the underside of the swell, marvelling at the feel of it. It was almost a shame that Bumblebee wouldn't know how sophisticated his new array was. He looked up to find Optimus watching him with something like amused affection, and reflexively hardened the line of his mouth. "But it will be at comparatively slow rate – representative of the estimated seventeen months rather than the native nine."

Pulling the shirt back down from beneath the holo's breasts, Optimus rested his hands on his hips. "I shall just have to be discrete about using it." Anything more was cut off by a cramp through the newly-realised organs, and his human counterpart betrayed a grimace far more obviously than his mech form.

Ratchet's holo abruptly vanished, and peripherally he saw Optimus's fade out as he came around the berth with scanners flashing. "What?"

Eight months ago, Optimus would have waved off the medic's attention over so trivial a feeling, but he had learnt the hard way that certain aches and pains were signs of the sparkling's welfare. Thus, they deserved whatever degree of attention Ratchet thought was necessary.

He followed Ratchet's gesture to sit up on the berth, parting and retracting the necessary plates as probing hands scanned deeper. As an afterthought, he removed Shockwave's Cybertronian from the compartment and set it aside on the berth so as not to confuse the scans. "I've not been able to process energon properly since last night, and my sump systems have turned hyper-sensitive for it."

Ratchet hummed a low sound of disapproval, moving away from the berth to retrieve a mineral supplement vial from a storage cupboard. He pressed the cylinder into a delivery needle, and then injected the contents into the primary energon line lying exposed in fragments in the mech's chassis. "There's not much I can do other than top up some of what you're losing. Hopefully the purging spell will pass without harm as it did before."

Optimus nodded fractionally, though in his spark he was unconvinced. The symptoms were identical to those he'd experienced two months ago, but that it had only signalled a large recalibration on his systems and nothing dangerous did not reassure him now. He knew that he would worry for the sparkling's survival up until it had been delivered, and then turn to a whole other kind of fretting.

After withdrawing his hands and gesturing for the taller mech to close, Ratchet noticed the silvery item on the berth with a sharp vent. He didn't need to touch it to confirm what the material was, but picked it up all the same to affirm its solidity and realness in this place. "Cybertronium? Optimus, where in Straxus did you get this?"

Dimly glad of the distraction, Optimus shifted down from the berth and led them both to the Medbay's primary console, keying up the first report from Las Vegas. "The larger concern is _how_, Ratchet." He went on, heavily: "And I fear that its presence on this planet dwarfs this sparkling in importance now."


	8. Chapter 8

Warning for lots of angst in this chapter.

* * *

><p>Only a Prime<p>

_Chapter Eight_

* * *

><p>2 Days later<p>

* * *

><p>Optimus wasn't sure what had actually woken him from recharge – the comm. alert, or the corrosive pain building in his chassis. After a stunned moment of motionlessness, he twisted himself up to sit on the berth with a hand to his chest plates. A swell of extreme nausea and the pain increased tenfold, causing his backstrut to curl.<p>

"No, little one. Please don't," he murmured into the dark, optics shuttering and dentals gritting as he tried to will the cause of the sensations away. It was pointless, he knew, and he opened the persisting comm. line as a distraction. "What?"

Silence for a few seconds as Ironhide absorbed the snapped word, finally speaking as if nothing were amiss. "Had a landing in Sargasso a few minutes ago. No response to Autobot hails, and it's putting out a very bad dispersal pattern."

Decepticon, more than likely, Optimus surmised with a hard grimace as he pulled the waste bin out from under the berth and set it on the foam next to him. His fans stuttered mid-cycle, fuel lines spasming, and he rested an elbow on the bin. It was a familiar preparation. "How far out to sea was it?"

"Hundred and a bit miles," Ironhide grunted, and Optimus had a flash of him leaning over a console in the monitoring room. "Gives us time to get the welcoming committee ready. Lennox is on his way."

"I'll inform the defence secretary," Optimus replied before muting his end of the channel to retch the majority of his fuel tank into the bin. The spasms bringing the energon up only compounded the pain around the gestation chamber, and he brought a knee to his chest as a kind of brace.

The long silence heightened Ironhide's earlier concern. "Are you alright, Sir?"

It was almost a full minute before Optimus could answer, coughing up tainted dregs whilst his hands trembled against the sides of the container with physical shock at another death against his spark. When he finally spoke, his vocaliser was hoarse. "I'm alright, Ironhide. Prime out." He cut off the channel before the dark mech could respond, trusting him to do his job. He would need to move to his office to make the call, but for the moment he could only rest his head in his hands and let the worst of the purging pass.

When he was relatively certain that his tank was empty, he forced himself from the berth and to his feet despite the cramping aches it brought about throughout his body. Walking sometimes helped, and he had to refuel despite the nausea. Moving to the dispenser in the wall, he opened the tap and filled a cube with energon from the main line. Another significant improvement they'd been able to make in their Base, and it meant that he didn't need to go to the refectory to refuel.

Optimus retreated back to the berth with the cube and sat, shifting the bin aside with his foot to incinerate the contents later. He'd been starkly aware of his chassis since waking in the Medbay with the chamber installed half a year ago, and once again pressed a hand over that significant area with a sigh. "Primus keep you."

He didn't know how long his processor had drifted in a kind of haze before there was a single loud thump against the thick door – Ironhide's signature knock. Glancing to check that the bin was out of sight, though he knew that the other mech wouldn't need his optics to know about it, Optimus sent a wireless signal to the lock to let him in. Feeling as much as seeing the bright optics combing over him, he shifted to seem more composed than he felt before another cramping lance made him flinch.

Ironhide nodded at the simple yet comprehensive explanation. "It failed again?"

It was an innocent question based on misleading information, yet the simplicity of it to his audios made something in the Prime's chassis contract. Finally he made a soft sound of assent. "Unfortunately."

A single dark brow shifted upwards. "Told Ratchet yet?"

Optimus held up the cube a little though didn't offer the verbalised lie – he knew the procedure Ratchet would recommend, and the medic would know about it soon. Over time he'd found that he needed to be alone with this development for a period before Ratchet began a clinical forensic examination. It still confused him how he could grieve the loss of something he'd not truly had, and the failure of which he'd been prepared for since the beginning.

Whether Ironhide believed him from the gesture or not was unclear, but he grunted with a nod towards the door. "Let's walk it off – keep the energon moving so it can break down properly."

Another pang through his chassis, independent of the crude roaring that had taken up a permanent residence there, but Optimus led them out obligingly. In the corridor, however, he found that he had nothing to say – processor locked on the vision of the sparkling being disassembled one fragment at a time.

Giving the taller mech a sidelong glance, Ironhide bumped their arms as they walked. It was just wide enough to accommodate them both side by side, particularly this late at night when there was no traffic. "Ratchet'll get this figured out. He won't give up."

_Yet I might._ The words flashed through his mind of their own accord, and Optimus sighed with them even as he began to reiterate his internal diatribe as to why they had to keep trying. He could only assume that it was because the carriage had lasted so long that he felt this strongly over the loss.

There was nothing that could be done about it now, however, he affirmed with a momentary clench in his jaw. Straightening despite the pain, he triggered the battle mask to slide into place to mark a transition between mech and Prime in his mind and spark. It was a simple but effective habit he'd fallen into in times such as this.

"What do we know?"

The adjustment hadn't escaped Ironhide, though he made no comment on it. "It's either a ship we've lost the regs for or else a couple of massive bots – and we didn't have many Autobots that size when our army was good."

They stopped automatically outside of Ironhide's workshop, two doors down from the Prime's office. Optimus folded his arms in thought, subtly pressing against his chassis to bring the pain to a dull throb. It was taking longer to pass this time, it seemed. "In which case NEST should be organised for containment rather than engagement."

Ironhide grunted in agreement, turning to lean fractionally against the wall by the door. It was to convey that he wasn't done talking rather than for comfort. "I'll take Sideswipe and Tailbreaker up front." At the look Optimus gave him, Ironhide's optics darkened to a shine that was hard and immovable. "This is a bad one, Sir."

It was implicit to them both that the specialist referred to the medical failure, and not the possible threat of the coming engagement. Optimus brushed the curve of his fingers across his aching chassis with only a vague awareness that he had done so. "Only because it was further along. It's larger, thus it takes more energy to break down. As before, however, it isn't dangerous."

A single, slow nod, but Ironhide was far from convinced. "It'd still sit with me better if you were here rather than out in a fire fight."

Optimus stifled a sigh. "That may be so, but there is some time yet before we need to leave, by which point my systems will likely have readjusted."

Ironhide straightened to almost his full height, his vocaliser turning dry in contrast to the swell in his EM field. "If you say so. I come by later and you're still purging, though, I'm getting Ratchet to pull rank on your aft."

The tall mech found himself smiling faintly at the assertion, his own field soaking up the wave of familiar protectiveness. "I don't doubt it."

* * *

><p>"This is insane…"<p>

Sam's conviction in his quite reasonable assessment of the situation was somewhat diminished by the fact that he'd gasped it against Bumblebee's mouth. His holoform mouth, which was warm and eager and far too real for a construct of light and energy fields; not to mention his firm hands and pressing weight, seeping heat into his very core.

They were sprawled over the Camero's back seat, having moved from the front when it had become obvious that the plan to take things slowly with the holo was being abandoned. Bumblebee's thighs were parted over Sam's, their hips flush and shifting without any of the nervous hesitation that had been there when they'd first touched hands. Tentatively kissed, slow and thrilling.

It had frightened Sam at first that they were doing this inside the scout's true and in-motion form, driving up the Interstate on the way back from a patrol sweep. Bumblebee had started an explanation about tiered-processing and how operating his holoform was like driving whilst navigating and holding a conversation, and then Sam had run a hand up under his shirt and he'd not spoken since.

At Sam's utterance now, however, Bumblebee eased his mouth away to consider the other with bright, intent eyes. He touched a damp temple and drew his fingertips down with the same gentleness, still marvelling at the feel of organic flesh through these new sensors. "Too much?"

The soft question contained a dozen more within those two words, most of them too painful to fully iterate. Mikaela's presence hung like dead air around them, particularly potent inside this space. Every trace of her was gone, cleaned away chemically but impossible to expunge psychically.

But she was gone, and though it was awful and unfair, it was done. And fate had seen fit to offer something strange and wonderful now, and his life hadn't ended with hers. It was the best advice his father had ever given him, and Sam wondered how he'd respond if he knew it had been what had allowed him to accept the deepening feelings towards his extraterrestrial robot guardian.

Sam raised his own hand to cover Bumblebee's, pressing a kiss into his palm. "No. Just, me and an alien, getting it on." A quirked smile, bordering on shy despite the flush of arousal still bright up his throat. The hard pressures meeting between their legs. "It's, kind of insane."

Relaxing from a tenseness he hadn't realised he'd adopt, Bumblebee returned the smile and touched his nose to Sam's. "Stranger things have happened," he murmured, eyes closing again as he sunk back down to that intoxicating mouth.

In his true form, the scout's spark pulsed and triggered a fresh burst of power through his engine. The speed camera flashed as they tore past, holding up their velocity to the night in clear, red digits.

* * *

><p>One of the many mixed blessings of the Hoover Dam base was its size. With full approval now granted to allow the Cybertronians to make Earth their home, however temporary, renovation of the facility had been to their consideration. Now, the automatic doors dwarfed the humans who passed through, and the corridors were long. It felt like it fit them. It felt like they belonged. It gave Ratchet far too much time to fume.<p>

"_At your convenience_," he muttered darkly in refrain, passing the refectory doors. Six hundred yards of various workshops and offices before he reached the Prime's. "Slag his manifolds – I'll give him _convenience._"

He wasn't truly angry with Optimus, but amidst the roiling miasma of emotions, that was the one he was prepared to deal with. That he was having to make this trek at this un-Primus hour because Optimus wasn't in his quarters adjacent to the Medbay, as he should have been, was a large part of his anger. The not-making-a-fuss tone of the comm. message that had been quietly _left_ for him comprised the rest.

The door was code-locked and protocol was to knock, but no door had been locked to Ratchet where Prime was concerned in almost a year. Seeing that the mech was in conference, however, he did wait against the wall after sealing the door behind him. Optimus was pacing and using audio only, ignoring the specially installed screen on the wall. His face mask was in place, Ratchet noted with a sigh, and his sensors needn't have supplied that he'd been purging.

To Ratchet, Optimus gave a short nod of acknowledgement whilst walking the length of the sparse office. "I'm afraid I cannot condone that degree of response, Madam Secretary. Water is not a natural element to us, and unless the landed Decepticon is a Seeker we have several hours to ready an engagement. I will connect you to my tactical officer now to discuss the details."

It took several more minutes to conclude the call, in which time Optimus had moved to sit at his desk with one hand resting on the half-drunk cube of energon placed there. Ratchet waited until the signal had vanished from the dampening field before approaching the desk, his arms folded. The bristling anger had bled away entirely, now. "You should have come to me directly."

"I know the procedure, Ratchet," Optimus replied quietly, lifting the cube demonstrably though the mask remained fixed. "Allow the purging but refuel as much as possible."

A low sound and Ratchet came around the desk to lean against it, optics bright with scans. "When?"

It was a simple question but loaded with more than they had ever spoken about. The more it happened, the harder it got, though Optimus sensed that they were both becoming numb to it. Or perhaps cold.

"During recharge. I came online processing the, impurities, at 02:28." Optimus trailed off with shuttered optics, one hand brushing over the small plates as his vents gave a shudder. It was vastly different to the nausea he'd been afflicted with on and off for the last few weeks, carrying with it a cold weakening and a bitter ache throughout his body. "It's, worse than it has been before."

"That's to be expected," Ratchet replied, his gaze fixed on the other's bowed helm. "The further along, the larger and more complex it is, and the more taxing to disassemble and absorb." He gritted his dentals at his own words, momentarily hating the clinical shield that was in place for both their sakes.

Beneath his medical programming, the urge to comfort and soothe the mech after each miscarriage wasn't diminishing. But he could not open that door and allow his professionalism to be coloured when Optimus needed him as a medic more than as a friend, and he sensed that if he dared to put an arm around him as he ached to, the Prime would finally come undone.

"I truly thought this was it," Optimus admitted, breaking into the other's thoughts. He dropped his hand and met Ratchet's optics, sitting back in the chair. The purging seemed to have stopped now, though it was still uncomfortable to have any significant amount of fuel in his tanks. He shifted a little at a new cramping pain in his chassis, no doubt as more materials were forcibly drawn out through the walls of the gestation chamber for processing and reclamation within his systems.

With a sigh he blocked the mental tangent, setting the cube aside and producing a datachip from a drawer. Vital statistics were being logged constantly from an internal scanner, but Ratchet had recently supplemented this monitoring with a more informal journal of his daily wellbeing. They hoped that it would help to pinpoint what had been going wrong each time.

"This is the longest one has lasted," Optimus remarked with forced lightness, handing the chip across. It was recorded up until an hour ago, when he'd simply lost the will. "We should begin reviewing the logs to-"

Ratchet broke in before he'd finished composing the words, his hand raised. "Perhaps we should take a break from this."

Setting the chip onto the desk, Optimus rose to his feet to physically underline that he was fine. "There's no medical need to wait more than a day before trying again," he reminded evenly, though it sounded weak to his own audios.

Ratchet huffed. "It's not medical harm I'm concerned about."

Optimus had only moved a step away, but turned back at the admission and reached as if to touch the medic's arm. It had been a purely instinctive reaction, some unconscious need to have physical contact, suppressed as quickly as it had arisen. He folded his arms instead, though his expression didn't back the posture. "Please, Ratchet. If you are able to continue, then I want to as soon as possible."

A long, critically measuring look that quickly turned into a silent battle of wills. When Prime's optics didn't so much as flicker, Ratchet grumbled an ex-vent and folded his arms as well. "Fine." He nodded his chin upwards. "What's this engagement about?"

The Prime didn't miss a beat, glad of the topic change. He looked to the wall-screen as he wirelessly activated it, showing the location on the dark map as a neutral-green light. It would turn either red or blue the moment they knew a faction. "There's been a large, possible Decepticon landing in the Sargasso sea. No communication thus far, and the energy signal is only beginning to approach land. We'll dispatch to intercept in an hour."

Ratchet arched one brow, looking to the taller mech with all the subtlety of an iron bar. "We?"

"I'll be leading the team," Optimus replied flatly. He shifted fractionally, trying to ease a toxic cramp building beneath his spark. "I'm not carrying, Ratchet."

"No, you've just miscarried," he quickly clarified, forcing that word into the room despite how he knew it would make Optimus's optics harden. Autobot Commander or not, Ratchet still held medical rule and wouldn't hesitate to remind Optimus of that.

Optimus's gaze did indeed harden, but the thin plates around his optics also tightened to narrow the dimmed, pained glows. "And I can think of few torments worse than resting here when I don't need to thinking about that, whilst the Autobots risk themselves without me." His voice trailed away with a shiver, helm bowing and optics shuttering fully.

Instantly Ratchet moved from the desk to lay critical hands on the large mech's chassis, a medical line from his right wrist latching straight into a data port even as his scanners combed familiar systems. "It shouldn't still be this bad," he murmured, his optics falling out of focus as he sifted through the miasma of just-off readings that were starting to come back. "Talk to me, Optimus."

It was almost automatic for him to shake his head, trying to dispel the mounting concern even as Ratchet's hands shifted, seeking. "I'm alright," he finally uttered, declining to admit that this was the worst it had ever felt. "I've become accustomed to this."

Ratchet hummed a negative, optics narrowing back to focus as he collected multiple sensor threads together and found them coalescing. Micro systems – valves to keep fuel circulating in the right direction; coolant sieves; transformation lubrication nozzles – all seizing up in a wave of minor cascade failures. Building into more substantial failures, and quickly approaching a critical apex.

Because the sparkling wasn't being absorbed. It was lying dead and putrefying.

"You're going to the Medbay, now." A hand grasped his shoulder with sudden force, and Ratchet looked up in alarm. "What?"

"My primary sensor grid just went offline," Optimus replied, terse and disturbed by how suddenly his entire frame had turned numb. The loss of sensation had taken with it the pains and pressures of the dead sparkling, but left behind a queasy hollowness and a sense of falling.

"Primus, this is why I wanted you next to the 'bay," Ratchet snarled, already wrapping an arm around the tall mech's shoulders and bracing his legs as he guided his weight down to the floor. "Sequential system failure - your core systems are trying to preserve themselves from the toxins and failing miserably. I need to get the sparklet out. Here'll do." He laid hands on the broad chassis, already applying force. "Open up."

Optimus complied as much as his failing systems would allow, but the medic's hydraulics had to do much of the work. He reset his optics, attempting to use the simple command to bring some of his systems back into synchronicity. Errors swarmed against his processor, though he could feel Ratchet's assured digital presence soothing them away through a hardline connection.

As when the chamber had been installed, as during the scans following every loss before today, he skirted his attention as best he could from what Ratchet was doing. Focus instead on what he could do to help – to calm his systems as much as possible so that the medic could work with as little difficultly as possible. To imagine the movement of air through his vents, stealing away dangerous heat and moisture, and not the thing that no longer was.

"Can you move your pedes?"

The question fell from nowhere, and Optimus was disturbed by how far his mind had drifted. Testing the answer only troubled him further. "No."

Ratchet glanced up to the prow of the battle mask, his own jaw tight with concentration and a tangle of other emotions that he truly did not want to deal with right now. "You'll be fine. Just stay online for me," he uttered softly, as he would to any patient on the verge of sinking.

Working with expert skill, Ratchet kept his hands clean of fluid as he negotiated the interlocking parts that had been paralysed by the system failures, reaching scarred protoform within seconds. The wound had healed well but it was still an ugly breach, and came apart messily when he slid the laser scalpel swiftly through it. Revealed, the gestation chamber was oil-shiny and distended in a round swell. In a month, the distensions would have been slighter but angular as the protoform unfurled and allowed its limbs to fletch. Right now, it would be like removing a stone.

When he'd made the artificial organ, he'd installed a resealable strip where the neutral breaching point ought to have been. Pragmatically he'd known then of the likelihood of miscarriages, and the possibility of needing to extract a sparklet too far developed to be naturally deconstructed and absorbed.

A stiff intake of air from Optimus, and Ratchet peripherally saw a hand twitch upwards from the floor. "We cannot lose the chamber."

They both knew that they couldn't make another– there had barely been enough material to make this one. Ratchet rumbled an irritable sound, damning thrice-over the Prime's diminished sense of his own worth for the thousandth time since they started. "Or you – that's what got us started on this whole fragging farce."

The mesh-like strip split apart under the laser cleanly, releasing a rush of fluids that quickly began to sizzle on overheated parts. He slid the tips of his fingers into the wound, felt solidity on the other side. "Alright, here we go."

Pressing his hand inside to scoop the content out as quickly as he was able, Ratchet didn't look at the thing until he'd laid a patch-gel over the gap. Through the datalink strung from his forearm into a port in the other mech's shoulder, he sensed as much as read the alerts beginning to ease and cycle down. Now that the source of toxicity was removed, scrubbers and several cubes of refined energon would correct the rest.

Ratchet sat back on his haunches with his cradling hands raised, optics fixed on his palms but absent of any scanning beams. Too small to determine a sex, or even hazard a guess at frame structure, but it was a real sparkling splayed in his hand like a baby bird fallen from the nest. A sparkling. A Prime sparkling. Their sparkling. His, as well.

Optimus's chassis remained open to the air to aid cooling, and slowly his helm drifted to the side to watch the medic. He hadn't wanted to look, but he was not a mech to shy away from facing his failures. And this felt like a most staggering failure.

"What am I doing wrong?" he asked softly, and it seemed as if the agonized question was posed as much to the lifeless form obscured from his view as it was to Ratchet. "What am I doing to kill them?"

Ratchet's reply was immediate, and it would have sounded terse if it hadn't been so wearied. "You're not doing anything 'wrong'." He shook his helm fractionally, feeling his chassis ache with his own sense of failure against the grief of the loss. Of Optimus's loss. "I just haven't worked out why the sparklings keep failing without cause."

A high whine signalled movement before the parts hastily calibrated themselves, and grateful that his motor relays were returning to normal, Optimus rested one hand on the medic's knee. Over the battle mask, his hazed optics drifted. "Do not blame yourself for this, old friend. That you gave me the means to try is astonishing in itself, and-"

Azure optics sharpened, the sparkling in his hands superseded in his attention. "Optimus?"

When the large mech didn't respond but rather frowned with concentration at whatever had caught his attention, Ratchet twisted to follow his gaze. On the digital display Optimus had brought up to display the landing site, the coloured indication had changed colour from neutral green to Autobot blue.

A crackle from the Base's intercom system preceded Ironhide's voice, and they could both hear the grin in it. "You won't fragging believe this, Prime. Wheeljack's just in. It's him, and he's brought the Wreckers."


	9. Chapter 9

Only a Prime

_Chapter Nine_

* * *

><p>Optimus stiffened, bracing a hand against the floor to try to rise. His systems kept him from doing so before Ratchet's hand pressed firmly against his chassis.<p>

The medic left him with a stern look, transferring the sparkling into one palm and producing a piece of tarp from subspace. "You're on medical leave until further notice. Ironhide and I can handle the Wreckers." Then, aloud and through his comm., he replied: "Dispatch Sideswipe and Bumblebee to meet them, confirm idents' and lead them here."

There was barely a pause before Ironhide's voice came back, clipped and sharp. "Where's Prime?"

Glancing to Optimus, expecting him to try to comm. back first with some kind of dismissive assurance, Ratchet found the mech staring silently at his hands. Specifically, at the tiny body he was gently wrapping in the tarp. He closed his hands around the shroud, a tremor passing through his digits as he detected the rapid dissipation of heat from the grey body.

"Ratchet?"

"Office," he replied curtly, not flinching at the agitated snap in the specialist's tone. "I could use a servo getting him to the Medbay. Ratchet out."

Optimus shifted, about to protest before the older mech cut him off with a hard click. "He'll stay in the dark, Optimus, don't worry." A pause, and Ratchet's tone softened in an unwitting reflection of the ache in his own spark. "And I do need his hands to keep you stable. I can't close until the chamber's cooled."

His optics fell to the small, solid parcel in his hands. Softly, and having to force himself to meet Optimus's gaze, he asked, "Do you want to…" _Hold it? Say goodbye? Bury it?_ He didn't know the end to the pitiful question, and it was all beyond his ability to say anyway. As was nauseatingly become habit since they'd started on this venture, he felt utterly useless.

Chassis wrenched apart to weeping, smoking protoform, Optimus put a hand on the medic's wrist. Ratchet tasted energon from biting his glossa at the gesture, feeling his spark give a bitter clench. He should not be the one who faltered, here. Should not need comfort and reassurance from the patient. But this gesture, this selfless offer of comfort was fundamentally Prime, and a clear summation of why they were trying so desperately to make another.

That, Ratchet privately admitted, and because he wanted his sparkling too.

"It will be alright, Ratchet," Optimus intoned, though it sounded weak and laboured to his own audios. "There is always hope, and today we are reunited with old friends and comrades. I know you and Wheeljack were close."

Shifting the bundle into one hand, Ratchet settled the other over Optimus's wrist with a sigh. "Optimus, I will figure this out," he said, flat and hard, the sub-harmonics of his voice and the potency of his field wreathed in solemn oaths. "I swear it to you. And if-"

The sound of transformation outside was the only warning before Ironhide burst through the door, having sped in alt. mode from the control room. It was long enough for Ratchet to slip the bundle into a shoulder compartment. Inside, it felt like a lead weight.

"Ordered everyone out of the corridor. Way's clear to the Medbay," the dark mech uttered for Ratchet's benefit, though his optics were fixed on the Prime. He came to kneel at the tall mech's feet, openly scanning over the slick mess of his chassis, taking in the tremors of shock in his lines. Ironhide shook his head, optics bright. "Primus, look at the state of you."

Optimus cycled a vent, relieved that he could at least do that much now. "It looks worse than it is."

Ironhide's mouth slanted into a crooked smile, the initial system-wrenching panic easing a little at the ridiculous and blessedly predictable reassurance. "Like scrap it does. Gonna keep you confined to the Medbay _myself_ after this." His expression sobered when he looked back to Ratchet, whose deft hands were syphoning out murky energon and polluted coolant from the Prime's chassis before it could burn and crust against his internals.

"What in the Pit happened? And what can I do?"

Ratchet didn't pause in his work, one hand resting over the chamber to protect the fresh seal whilst the tube from his other wrist sucked away the viscous mess. He knew Optimus was watching him from the weight of his focus rather than through his peripheral vision. Whether he was looking at the obfuscated body or simply wondering if Ratchet was about to relieve some of the burden of his guilt by confessing the whole mad scheme to Ironhide, he couldn't tell.

The medic did not give Optimus time to react, much less protest, before snapping a cord into an ancillary node inside the mech's gaping chassis and triggering stasis. When the long body fell slack to the critical optic, Ratchet motioned for Ironhide to approach.

"Take his other side and help me carry him. Quickly." When Ironhide's field crackled, Ratchet shook his head a little with an exvent, manoeuvring his hands beneath thigh and chassis. "He's fine to move, but he'll be _better_ in the Medbay."

Ironhide fell silent, though his expression spoke volumes as he helped collect up the Prime's body as if it were made of glass. As they began the agonizingly slow process of moving Optimus to the 'bay, Ratchet found that he couldn't met the mech's scrutinizing stare.

Nor bring much of his focus out of that shoulder compartment, where the sparkling's corpse slid against his frame as he moved.

* * *

><p>2 weeks later<p>

* * *

><p>Wheeljack couldn't have arrived at a better time, in Ratchet's mind. There had been some changes in his old friend, such as the loss of the nervous-awkwardness that used to haunt his gait, but it was still Wheeljack. Older and more confident, with scarred and thicker plates, but still Wheeljack.<p>

He'd brought four Wreckers in tow with him on the Xantium, presently left on the sea bed where it had landed whilst NEST figured out how and where to move a spaceship without several million civilians noticing. A wide green mech, Bulkhead, had stood close to the inventor's shoulder when introductions were made. Behind them, Leadfoot, Roadbuster and Topspin were all that was left of the crew.

From the official reports, sheer determination and tactical brilliance in the face of overwhelming odds had seen them escape hounding Decepticon forces to follow the Prime's transmission. Off the record, Wheeljack had said that, in typical Wrecker style, their arrival was more the result of suicidal audacity and dumb luck.

Ratchet had performed all their physicals, absorbed the reports from the deep black that hadn't managed to make it to their unit here on Earth, and greedily combed the Xantium's inventory. There was an honest-to-Primus stocked and equipped _medical bay_ on board; as well as weapons, ammunition, rations, replacement parts and a myriad of other essentials that Ratchet had spent decades thinking of as precious luxuries.

In turn, the Wreckers had found new enthusiasm and energy for being amongst the Prime's team inside the security of the Hoover Dam. Megatron himself was on this planet, making this the front line of the Autobot/Decepticon war, and there were regular skirmishes between his most powerful warriors and their own. Leadfoot, Roadbust and Topspin had taken over an entire storage room with schematics of weapons and physics-bending propositions for instruments of war. Wheeljack's interests had clearly rubbed off on the engineers. On the third day after their arrival they'd requested Optimus's alt. mode schematics for their Project: Mobile Battle Station.

All in all, there had been plenty of distractions from the fact that Optimus was barely speaking to him. It had taken two days for the mess of the Prime's chassis to be put back to rights, and though he'd been discharged on strict medical leave, the mech had still been able to busy himself for most of each day without an official breach. Clearly he did not wish to dwell any further on that disastrous time on the floor of his office, and Ratchet had given him that space.

He'd snarled to himself that his motives were far from professional - selfish and cowardly – but there was enough going on with the Wreckers to excuse himself. Just.

This morning, Ratchet was taking Wheeljack for a more thorough tour of the base to discuss modifications in Optimus's stead, whilst Ironhide showed Bulkhead around the areas that were primarily NEST. The medic had yet to stop smiling. A month ago he could not have conceived of spending a full hour away from the Medbay like this, without thoughts of the failing sparklings dogging at his processor. It was a welcomed change.

"There's a store room two levels down that could easily be overhauled into a proper lab. Power-wise it's more suitable that that makeshift space your mechs are occupying now," Ratchet went on as they came into the Medbay. Wheeljack immediately began exploring, obviously pleased to be amongst the familiar equipment. "If you want the same set-up as you did on the Ark, we can attach quarters straight off of it."

"It'd have to be roomy," Wheeljack replied, turning away from the workbench. "Bulkhead will be in there too." To Ratchet's stunned, though happy expression, he shrugged with a grin. "Mech's gotta keep warm in the black."

Though the words were casual, there was no mistaking the obvious affection and devotion in them. Ratchet leant against the side of the examination berth with folded arms. "That's good. I'm glad for you. Though to be honest, 'Jack, I wouldn't have thought him your type."

Wheeljack nodded a little, conceding the point with a raised brow. "We stuck together after the Ark was lost to increase our odds, and over the years… He's a good mech. Spark bigger than his fists." The scientist cocked his head with a rueful smile that immediately put Ratchet on edge. It was only fair that they both divulged their personal lives, after all. "For you, though, I couldn't imagine anyone better than the Prime. Looks like we both got lucky."

Ratchet blinked at that, then realized that they had walked past the door with Optimus's glyph on it, recently made adjacent to the Medbay. Ironhide had pushed for Prime to move with far more tenacity than the doctor himself had, and had begun petitioning for his office to be relocated closer to the Medbay as well before Optimus had dismissed them both. Ratchet was beginning to think that Ironhide perhaps _needed_ to know the truth behind Optimus' 'affliction' and regular need for his care.

For the moment, Ratchet dismissed the train of thought with the same hum as he did Weeljack's assumption.

"There's nothing going on between myself and Optimus." A pause as he considered his words and his colleague. Wheeljack was now to be a permanent fixture of the base, and would pick up the scuttlebutt soon if he hadn't already. "He's undergoing long-term treatment, and it was practical to have his quarters adjacent to the Medbay for the time being."

The part of Wheeljack's processor that hadn't had much opportunity to come to the fore in centuries was suddenly roused. Though a scientist at spark and a warrior in build, he'd spent innumerable hours in Medbays putting his transferable skills to use. "Treating him for what?"

Ratchet held his gaze stiffly, giving nothing away, though he knew that Wheeljack as he was now wouldn't back down. Likely he could help, perhaps even figure out what was glitching every time, secrecy be damned. And above all, this was _Wheeljack_. He trusted no bot more with this information than himself.

Wheeljack braced himself when Ratchet sat back up onto the berth, shoulders low and hands dangling into the space between his legs. He could never have guessed the cause behind this pose.

"I built and installed a gestation chamber at Optimus's request," the medic finally uttered, feeling a strange mix of relief and shame at saying it. "We're trying to continue the Prime line now that the All Spark is gone."

Wheeljack held up a hand. The idea was so overwhelming that the 'how' didn't immediately enter his processor. "Prime's carrying? Carrying a sparkling within his own frame?"

Ratchet's expression flickered, twisted as the neutral mask failed utterly in front of one of his oldest and dearest friends. "Not since last month."

The Wrecker took a slow vent, the intelligent brightness of his optics softening at the edges. "I see. I'm sorry."

Heavy silence fell between. Ratchet felt it keenly, and felt the shame of his failures and the emotional turmoil he was subjecting their leader to anew.

Wheeljack suddenly straightened, turning on the wall screen with a wireless command. He knew when it was important to query and when it was more important to simply act, and he wanted that _look_ out of Ratchet's optics. The medic had been working alone in this 'bay with this audacious idea for too long, shouldering all its failures with no trained mind to reason him out of the guilt of it. But no longer.

In the past, Ratchet had come to his lab and his audacious projects to help when he could. Wheeljack had every intention of returning that long overdue favour.

He kept his back to the medic, fingers sliding over the controls to bring up everything in the computer about gestation and organ transplant, respectively. His field was professional and interested, but tellingly thread through with warm assurance and support. "Show me the data and talk me through what's been happening."

Once again, though not as widely as before, Ratchet was smiling. He took place alongside Wheeljack and called up the encrypted files.

* * *

><p><em>The next chapter is quite dialogue-heavy and about halfway written. Hopefully it won't be too long in the posting. Thank you to everyone who's stuck with me, and for reading this chapter. A review of any kind would be greatly appreciated.<em>


	10. Chapter 10

_An exceptional rare and wondrous convergence of inspiration, energy and free time brought this chapter out around a month early._

* * *

><p>Only a Prime<p>

_Chapter 10_

* * *

><p>1 month later<p>

* * *

><p>They'd found more tunnels under Sacramento. The Cybertronium growing through them was mesh-thin and easily removed, but the distance was startling. The senior officials and governing bodies had had to be informed, in part to contain the geologists who'd reported the erroneous soil readings that had flagged NEST's attention. Shockwave's creation was now a higher priority than Megatron. The main veins of the tunnels were being explored and the cybermatter transported back to Hoover. Amongst other things, the recently settled Wreckers had set up a smelt and forge to make use of the precious material so that the Earth outpost would no longer have to rely on scavenged parts and inferior native substitutes.<p>

Optimus was regularly out in the field, joining the Cybertronium convoys as both transport and guard. Ironhide was shadowing him like a hound. Ratchet remained within the confines of the dam and was thankful that the specialist constantly had optics on their commander. As things were, he and Optimus had not spoken of the sparkling that had been, nor any potential ones, since that morning in the office.

Ratchet had finally conducted the autopsy when Wheeljack had asked for the missing report, and hadn't expected to find the mech's silent presence a comfort as he studiously picked apart the tiny frame. Finding nothing wrong with it had been far worse than the looking. Four more months and its systems would have developed enough for it to have survived on external support if the chamber had rejected it.

Wheeljack's firm stance on the uselessness of such speculation had been the only thing to stop Ratchet from obsessing to the point of agony. But under the cool professionalism and steady manner with which he dealt with routine maintenance and repairs of the bots under his care, it was painfully clear to Wheeljack that the medic was still grieving.

And doing a pretty poor job of it, in his opinion.

Optimus he couldn't do anything about; aside from the fact that he wasn't even supposed to _know_ about this venture, they weren't close like he and Ratchet had been. So the Wrecker had plundered the 'secret' sill (the appearance of which had almost perfectly coincided with the Xantium's arrival), decreed that Leadfoot was a smart enough engineer to handle things in the Medbay for a day, and that if there _was_ an emergency, a shot of Faradium would soak the excess charge from their systems within minutes.

Ratchet had put up far less of a fight than he'd expected, which made Wheeljack think that the mech was in far direr need of getting cratered than he'd suspected.

He'd found them a quiet place way down in the sublevels where no one was likely to wander within audio range. There was a constant hum from the power house directly above them, backed by the muffled roar of channelled and crashing water. The lack of silence was soothing in a way that only came with living for centuries on a ship. Wheeljack had settled in against the wall of the mothballed storage room and, after the ninth cube, Ratchet was similarly slumped next to him.

It was inevitable that they'd end up talking about the sparkling, and the whole mad scheme surrounding it. Only now, Ratchet's frustration and distress were in the open, which was a significant improvement in Wheeljack's book.

The inventor was staring intently ahead at nothing, his focus turned inwards and his hand gesticulating through the shimmering fuel vapours. "It's not the gestation chamber – it's just not. It's perfect across the board, and there've been no signs of rejection post-op."

Ratchet was also staring straight ahead into the gloom, but both his hands were curled around his empty cube between his knees. "I've tried extended berth rest, mineral supplements, richer energon, sustained charge – _everything_." He lifted the cube, tried to drain it and then threw it in disgust when nothing came out. "I cannot understand why they keep dying."

Wheeljack cracked the seal on another cube from the stack and handed it across, watching as half of it was immediately 7swallowed with mulish intent. Deciding that Ratchet had now reached that very particular balance of coherent emotion and brutal honesty, he set his drink aside and laced his fingers. He let the chug, hum and rumble above them soothe for a few minutes, then finally looked at Ratchet's profile.

"Why did you only install the chamber?"

Ratchet rolled his optics so hard that his head tipped back against the concrete wall. "I didn't want to go down the psychologically trying route of installing an entire femme reproductive system."

Any other circumstances, Wheeljack might have been impressed that the mech could say such a syllabic statement following that much High Grade. At present, his engine just growled.

"'Psychologically trying'? Frag's sake, Ratch', he's already had three miscarriages. I think Prime's psychological welfare is a moot point at this stage." He raised a hand as if to cuff the medic, but only gestured up at the ceiling to vaguely indicate the base. "You've already put in the chamber, so why not modify the valve and hook 'em up?"

Ratchet planted a hand against the wall and staggered to his feet. His hand clenched as he took a step away to look down at Wheeljack, warping the cube. "That's entirely different and you know it. Artificially inseminating into an artificial gestation chamber is nothing like linking a mech's valve to it."

There was a sort of desperateness in Ratchet's optics, Wheeljack decided, but he was too irked by the dismissal to pay it any heed. "Like that's going to have a bearing on Prime's gender identity, or whatever it is you're so scared of." He wanted to get up and shake Ratchet –physically grab him by the shoulders as if denial could be rattled out like sand- but remained on the floor instead. Because he knew Ratchet would bolt, and was close to that already.

"Stop trying to protect him and do your slagging job." The sharp remark had slipped out before he could censor it. But Ratchet didn't leave. He stood utterly still, looking at the blank wall.

Wheeljack's jaw clenched, the sensor-laden fins on either side of his helm buzzing with frustration. He settled back against the wall and lay his wrists on his raised knees, but his expression remained hard. "You're protecting yourself. All the clinical distancing, using needles and fake charges to force his spark to overload. Didn't it occur to you that you need a dual charge to make a sparkling?"

"Ridiculous," Ratchet scoffed, though he didn't meet Wheeljack's stare as he said it. "Prime's spark has been more than sufficient to permit budding and growth, and furthermore-"

"They die." Wheeljack's expression had turned pained, his hands flared out imploringly. "Primus, Ratchet, you can't make a sparkling with needles and vials."

"You're not going to tell me that sparklings can only come out of _love_, are you?"

"No, but out of _heat_." Wheeljack left his cube on the floor when he got to his feet, imploring as he closed some of the space between them. "The spark of a Prime is all power and heat and _passion_, and you're not going to bring one into this world without that, no matter how hard you try."

Ratchet shook his head and stepped away, arms folding in a stance that was telling. "No: I'm getting closer. This carriage lasted for months. The next-"

"If you keep at this route, they're still all going to die."

It was like a slap to the face, stopping the medic in his tracks. The Wrecker got in close, stood solid and unflinching inside Ratchet's field. He brought his face so near that it was impossible for the mech _not_ to look him in the optic. "How many more are you going to make him lose before you take the next logical diagnostic step, _Doctor_?"

Ratchet's plates flattened and his jaw clenched. There was a warning flash across the refracting crystals of his optics, but it was a shield over a genuine pain.

Wheeljack felt no remorse for delivering the low blow, because Ratchet had needed it and he made sure to project that too. He eased away a little, returning some space. "Nature got it right before science did. If it ain't broke, don't go trying to fix it with something twice as complicated."

Finally, abruptly, the shield of professionalism fractured. Ratchet's shoulders dropped, and he rubbed his forehead with the corner of the cube. "It's not just that, 'Jack," he murmured through his dente, optics shuttered.

The agitation left Wheeljack's frame as quickly as it had Ratchet's, and he cycled a slow vent to absorb that admission. He lay a warm hand on the medic's wheelarch. His voice was quiet. "You can tell him that you don't want to be the other creator anymore. He'd understand, and I'm sure Ironhide or someone else would step in for you."

"No, he wants it to be me," Ratchet murmured, turning to face the shorter mech. Usually he would have shrugged off the hand, but right now, the supportive point of contact was helping. He told himself it was the High Grade lubricating his glossa, making him say things he hadn't fully confessed to himself. "And… Primus help me, I want this sparkling, too. But if we do it this way, if we …" He couldn't bring himself to say 'fragged'. It wasn't a word he could apply to Optimus. "Then it'd really be mine, and really be his."

Not the end result of a fluid donation, which was the most superficial difference. Wheeljack nodded with a thoughtful sound. "But would that be so bad?"

"If it failed then-"

Now Wheeljack did shake him, just a little, and with a dry sort of smile. "You'd have each other. And trust me when I say that it's better to have a friend in grief than a rank and profession."

* * *

><p>After the holoform pocketed the third ball in a row, Lennox rapped the blunt end of his cue against the floor. "Honestly, now: you've gotta be cheating to be pulling that in your second game."<p>

The tone was good natured, but Optimus still regarded the man quite seriously from where he'd bent to line upthe next shot. "I assure you, Major Lennox, there is no subterfuge. Even if my sensors were able to penetrate through the interferences designed to prevent the Decepticons discovering us to calculate the vectors, they're currently offline."

Not wishing to suspend a surprisingly enjoyable game, he slid the cue through the slim bridge of his holoform's fingers and nudged the white ball forward. The pink billiard rolled towards the pocket, but nudged to one side and didn't sink. Optimus arched a brow at it, much as he would a sheepish Bumblebee with a parking ticket stuck to his windscreen. "I'm relying on the view relayed through this form's optics, which, as you can see, is not sufficient for a perfect game."

Lennox grunted a laugh and put the blue cube of chalk to one side on the pool table. "Or just you're taking pity on a man years out of practice. And it's Will off-duty, remember?"

Optimus took a few steps back from the table as etiquette required. Whilst Lennox studied the layout, he looked across the rec room to where Sam and Bumblebee's holoform were playing a videogame together. They were sat close enough for their arms to constantly be touching, and when Bumblebee ruffled a hand through Sam's hair in mocking victory, his fingers lingered on the teen's neck.

The sharp _clack _of the billiards striking drew Optimus back, and he caught himself fiddling with the hem of his vest. The holoform's stomach was as flat as a human abdomen could be, but he continued to wear the heavy NEST jacket to obfuscate the curves of his body as if there was still something to hide.

Lennox had managed to ricochet the cue ball off the far cushion and score the pink. Optimus watched him set up his next shot. "Ironhide told me that Epps plays this game regularly."

"Yeah, _he_ calls it playing. I call it absolute destruction." Another pocket, and Lennox came past the holoform to the other end of the table. "Our dear Bobby Epps was a regular pool hall rat and hustler before he joined up. Fun for him, not so much for me. Give it a few weeks and you might be able to knock him down a peg or ten."

Optimus folded his arms, the cue tucked between breast and bicep. "We shall see."

As Ratchet had said when he'd advised against forcibly altering his avatar, he'd become comfortable with this form. It had provoked a few strange looks amongst the humans at first, and fewer questions, but the novelty had quickly passed.

Instead of taking the next shot, Lennox looked at Optimus with a similar expression to when he'd first seen the female holoform. The confusion was married with concern, though, and it was clear in his voice. He'd just made the connection between the last year of medical interventions and Optimus's earlier comment.

"Why's your sensor suite off? Are you hurt?" His hand was a fist around the top of the cue, thumb hooked around the chalked tip. "The real you, I mean."

Optimus held up a hand, arms still crossed. "No, quite the opposite." He regarded the table as he spoke, running the likely outcomes of his opponent's next shot and pondering how he may proceed. "My frame is currently undergoing maintenance and cleaning, and whilst the crew is very proficient, my sensors are unaccustomed to the little force they are using."

"You mean it tickles?"

The woman's mouth pulled to one side in a wry sort of smile, the alien brightness of her eyes glinting. "In places I could never hope to reach."

Lennox grinned at the admission, the tension that had gathered across his shoulders vanishing. "Fair enough. At least it's tickling and not, y'know."

Millennia old, the cultural and spiritual leader of his people, and having been around soldiers for the majority of his life, Optimus did not rise to Lennox's eyebrow wiggle. He raised his chin, the picture of dignity. "I would have still deactivated my sensors if that were the case. It would be highly inappropriate to do otherwise."

"Speaking of inappropriate," Lennox said, the rush of his words suggesting that he'd been trying to find a segue for some time. "Some of the juniors walked in on Wheeljack and Bulkhead in the corridor the other day." He bent to line up the cue. "I believe from 'Hide that the expression is 'trading paint'?"

Optimus had only been peripherally aware from the grapevine of the relationship between the two Wreckers. Recently he'd been spending large periods of time in the field with NEST, and the remaining time he had left in the Hoover dam was focussed upon confidential and decidedly non-personal matters. He'd not spent any time in the rec room, or talking casually with his team.

He was not avoiding Ratchet.

A missed pocket. Lennox picked up his coffee from the corner of the table without looking at Optimus, relaxed.

"We are thinking, _feeling_ beings, Will, and in some ways no different to your kind," Optimus finally replied in a soft utterance, neither apologetic nor lecturing. Without him really noticing, his holoform had turned to look towards Bumblebee and Sam again. The _clink_ of the coffee mug being set back down called back his attention. "But, I will have a word with them about discretion."

"Thanks. 'cause it raised a lot of questions I'm not even sure I have the vocabulary for," Lennox admitted with wide eyes, looking off to one side as if having a vivid recollection of something strange and unpleasant.

One of the pluses of the holoform, Lennox was finding, was that Optimus's human face betrayed emotion far more clearly than his Cybertronian one. In the Prime's natural form, he'd never have seen that tiny smile bordering on a smirk that was more in the eyes than the mouth. Optimus didn't show humour much, and it had become something of a mission to some of the NEST crew to get the big guy to laugh.

Lennox tapped the butt of the snooker cue into the floor as Optimus bent to make his next shot. Out of ingrained polite habit, he looked at the table and not the exposed swell of the hologram's breasts.

"Think it was good for them, actually, to see that same-sex relationships aren't anything unusual to a race of highly advanced aliens. Too many soldiers come out of basic full of horseshit ideas." Lennox paused with a frown, which he then rubbed at with thumb and forefinger. When talking to their new holoforms, it was particularly easy to forget that they were genuine 'from outer space' aliens with alien customs, cultures and biology. "That is right though, right? Not to get into the specifics, but Wheeljack and Bulkhead are male and someone like Arcee is female?"

Optimus abandoned the shot, stepping around to the other side of the corner to consider an alternative vector. He did so slowly, analysing the Major's question and considering how best to answer concisely. Ratchet was used to these sorts of questions, and had projections and slideshows already prepared to educate their organic cohort. Interesting as Optimus usually found conversations about their differences and similarities as races to be, he discovered he did not have the mental energy to engage in a protracted dialogue on this particular subject.

"There is more… _nuance_ to our biology in that respect. We do not have binary genders as you understand it, but rather a spectrum based on spark frequency and frame type. 'Mech' and 'femme' are categories within which many others lie." It was a poorly calculated shot, the white ball skimming its target and moving it an inch to the side. Optimus stepped back from the table and met Lennox's gaze. "However in the most equivalent terms – those of reproduction, you are correct."

Lennox nodded, but summarised to confirm: "Femmes have the babies?"

The lines around the holoform's mouth shifted, replicated jaw clenching spasmodically for a moment. "They did."

"I'm sorry," Lennox said, holding Optimus's stare as that somehow felt the right and respectful thing to do. The Autobots did not shy from the harsh realities of their lives, nor the devastating impact of their long war. That did not mean that it didn't wound them to reflect on it.

Optimus accepted the unnecessary sympathy for the gesture it was, making a soft sound that came out high from his human-female voicebox. "We can only hope that, somewhere, there are Cybertronians who felt it safe to have sparklings." He curled his other hand around the cue, looked over the table again, and for a moment couldn't remember whose turn it was. A synthesised sigh, then he added, "And that the war will end before we are unable to greet another generation."


	11. Chapter 11

Only a Prime

_Chapter 11_

Warnings for sticky sex and medical procedures.

* * *

><p><em>Three Months Later<em>

* * *

><p>The roar of cooling fans spinning at full speed was only just beginning to ease, however neither mech's systems would return to normal for several hours yet. Several emptied cubes that had once held Wrecker-strength High Grade were scattered about the floor, kicked and scuffed aside when the world had started spinning. Heat had built in the room over the last two hours, and their frames continued to give it off. The soft <em>pings<em> of their cooling armour were the only notable sounds, the rest of the base sealed off by the thick (and mercifully soundproof) walls.

Optimus shifted on his back, lifting away an abdominal plate that had gotten hooked on the other's pelvic armour. It had likely been tugging on a transformation seam for several minutes, but it was only now that he'd noticed it. The slight motion vibrated across the solid planes where their bodies were pressed flush. Before his partner could stir, Optimus soothed his thumb along a main ventral line, his other hand tightening its grip.

Their fingers were meshed. In the dark, he could feel the new seam where thumb and forefinger had been replaced after being torn off in Egypt.

He shuttered his optics, although the room was already unlit. _Egypt_.

After the Fallen's defeat, NEST had taken pains to remove every trace of Cybertronian technology from around and inside the Prime's ancient tomb. The Egyptian government had threatened violence before the ground beneath the other pyramids could be even partially excavated. It had turned out to be a grave miscalculation.

Shockwave's monster had erupted from the ruins of the Prime's pyramid, and onto the screens of hundreds of tourists. The resulting political fallout had been, in Lennox's terms, a 'clusterfuck of a shitstorm', and Optimus was inclined to agree. It had been thirty hours before they've been able to access the site, and five more to confirm that something was missing.

Wheeljack had only been able to detect traces of energon concurrent with non-sentient Cybertronian systems, meaning that the tunnelling machine had taken a relic or some sort of equipment. His scanners could not make a guess at what, and the cavern left behind held no other clues. As expected, thin webs of Cybertronium had coated the churned sand.

Optimus fidgeted again on the berth, though not out of some minor physical discomfort this time. Ironhide grumbled something against his collar faring, and he stroked his thumb between the plates of his shoulders again to settle him.

The older mech had been standing close when he'd struck across the innocuous area of sand where the Matrix had reignited his spark. He'd felt a strange, cold pulse throughout his being, bringing with it the painful minutes bracketing his death to the fore of his mind, and then nothing. Ironhide hadn't asked, hadn't spoken; just touched a hand to his arm. A reminder that, despite everything, he was still here.

They'd been celebrating as much every night since returning to the base. At least, that was how Optimus had chosen to rationalise it. Through the muzzy fog of overcharge, however, he knew that the decision to rekindle their old physical relationship was rooted in something far more _base_.

* * *

><p><em>Two months ago<em>

* * *

><p>When Ratchet had refused to hold his gaze, Optimus had resigned to watching the water crashing down the dam below them as the medic outlined his proposal. They were sat on the ledge of the Hoover base, the roaring tide that powered the generators of their home tuned down in their audios to a background murmur. It was rare for them to spend time together outside like this, and Optimus had suspected that Ratchet's invitation to an unusual locale was indicative of an <em>unusual<em> discussion.

He hadn't been wrong.

"To be clear," he began, looking to the other mech's profile. Ratchet's obvious unease was new, unsettling and contagious. It was doubtful that he would be able to coax out _why_ the older mech was practically squirming in his plates right now, and Optimus was well versed at being firmly resolved when others were uncertain.

Even if parts of his _own_ mesh were practically squirming.

Optimus touched a digit to the thin plates above his mask, pressing away a stray-charge twitch. "Would my current interfacing, equipment, be altered?"

Ratchet straightened, suddenly animated as he shook his head. He seemed to make a deliberate effort to look up from his dangling pedes, hands gripping the concrete ledge either side of his thighs. "No, not at all. All this would be is connecting a conduit from the back of your valve up to the gestation chamber, as femmes are structured. You'll still effuse in the way you did before, except this way some of it will be redirected up into the chamber. Before you were sparked it was a relatively standard, albeit specialised, procedure for cohorts wishing to carry a newspark but lacking the hardware. Mechs, primarily, though there were also femmes who required a replacement for one reason or another."

"Alright," Optimus replied, purely to show that he understood. He held Ratchet's gaze, which in turn forced Ratchet to hold his. "Would there be any other modifications?"

There was a faint rumble in the distance: a NEST transport truck, their sensors quickly confirmed. Ratchet seemed to compose himself fully in the short time he watched the road, looking back to Optimus with clinical calm. "Wheeljack and I are looking into the possibility of manufacturing a small fabrication plant, to replace the solutions you've been ingesting orally, also akin to a femme. If I were to install it in addition to making the link with the chamber, there would be no obvious structural differences."

Optimus nodded again, optics brightening as he processed the potential implications of these changes. When Ratchet had told him that he'd elected to bring in Wheeljack's expertise, and assured that the pursuit of a Prime sparkling was still held in the strictest confidence, Optimus had been pleased. The Wrecker would be a valuable consult, particularly with regard to his innate divergent and unorthodox thought strings. Doubtless this proposal to bring his valve and a dual overload into the equation had been, at least in part, his idea.

He cycled a ventilation, sorting through his thoughts with the same due care and attention as he had when giving final consent for the gestation chamber to be installed. It did not take long to guess at what was troubling the medic, at the very least from an ethical standpoint.

"And the… delivery of your nanites?"

Ratchet raised his chin a little, though to what effect Optimus couldn't say. His lip plates tightened. The silence drew out long enough for the truck to pass on the road above and behind them, its engine fading into a purring murmur. Finally, the smaller mech replied, "There've been innumerable sparklings produced from artificial insemination"

Optimus frowned openly now, allowing his concern for this uncharacteristic avoidance to bleed into his field. Ratchet's own energies were a low buzz, held tight and close to his plates, which only heightened the Prime's unease. He had already made the connection -it was obvious- but that Ratchet was clearly avoiding saying it made him want to hear it,

"But?" he prompted with a soft note of authority, his optics attentively bright.

The façade cracked with a rattling sigh, Ratchet's frame visible sagging as if under some relentless weight. He brushed a hand over his optics. "Wheeljack… Suspects that that won't work for what we're trying to achieve. For a sparkling of Prime lineage. He thinks that a close-proximity, duel overload with direct transmission through a charged channel would… yield better results."

And be complete mimicry of usual procreation. Optimus gave Ratchet the space of not being watched for a moment, considering that himself now that words were in the air between them.

The 'natural' method was close and hot: transfluid was taken through the valve and supercharged by the carrier's overload as it was carried up, the very act of insemination acting as a catalyst whilst beneath the swollen spark, the chamber flushed hot and ready. Many femmes of every frame type claimed to have been able to feel when a sparklet formed inside them. It was emotionally charged, for all involved.

He was not prudish, and culturally Cybertronians had never been timid, shameful or judgemental about interfacing (aside from the caste divides), but the thought of laying with Ratchet in such a way gave him pause. It would be to veer entirely from the relationship they'd sought to maintain since that first conversation two years ago. They'd been studiously professional to keep duty and emotion separated; catagorised their efforts as purely creating a sparkling of Prime lineage with the initial involvement of as few as was possible, not of creating a sparkling together. Optimus could be honest enough with himself to see that he would find that distinction… challenging to maintain if Ratchet stopped using a needle to deliver transfluid into his chamber.

And he wondered, too, if Ratchet would struggle with that line in the sand. Optimus could remember, in far greater detail than he cared for, the unguarded look on Ratchet's face when he'd held the last, most formed sparkling.

The Prime straightened from where he'd hunched over the ledge, suddenly decided. Wheeljack and Ratchet, together, felt that this would give a sparkling the best chance of success. The best chance of never having to see that look on Ratchet's face again.

"I understand," he uttered, optics bright with resolve and the words underscored with glyphs of consent.

Yet it was not so simple as just making the decision. With the Decepticons under the radar and Shockwave's tunnelling machine still at large, the time for material preparation and recuperation to battle readiness had to be accounted for in addition to the operation itself. "How long would it take to recover from this procedure?"

Ratchet seemed to almost cringe at that, shoulders tightening and dente gritting. He lay a hand "Optimus, please. I've already mutilated you, had you suffer four miscarriages."

There was a warmth in the Prime's chassis, reassuring and ancient, leeching away his anxiety. The Matrix, he assumed, though he wouldn't mention the relic's possible support to reassure the medic. Ratchet did not place much stock in combining mysticism with medicine in the most detached of terms.

Optimus lay his hand atop Ratchet's, squeezing. "I'm at peace with this, old friend. This is far from the first time I have sacrificed my body for some greater purpose, or that we have overcome obstacles and setbacks to achieve our goals.

As expected, Ratchet pulled away with a growl. Optimus didn't resist the withdrawal of his hand, nor flinch when the mech's field suddenly flashed hard and hot. "This isn't volunteering to take the All Spark into your chassis, or losing a limb in battle, or even dying getting run through by Megatron, for frag's sake. This is about, a fully functioning reproductive system where it was never intended, on this primitive, dirty world with make-do equipment."

His hand began an emphasising chopping motion as if he were lecturing a class. "Before the war, there were systems in place for this sort of thing. Institutes dedicated to modifying frames to match spark resonance. Specialist equipment. Counselling-"

"Will there be a better chance of carrying to term?" Optimus cut in, breaking off the tirade before Ratchet could really get going and talk them _both_ out of it.

There was a long pause whilst Ratchet calmed himself, then finally: "Wheeljack believes it would be significantly improved."

"And you?"

Optimus wanted to hear Ratchet say it, and he damn well knew it. He couldn't be agitated at the blatant manipulation, though, and simply rested his hands back in his lap. "Yes. I think it would."

The medically advisable route now taken precedence over the potential minefield of emotional complications, Optimus's mind turned to the other question at hand. Whilst they'd been injecting generative materials directly into the chamber, the intention was to remove the developed sparkling when the time came through the same point of entry through his chassis. If, as Ratchet had posited, the point of entry for the nanites was changed to a modified valve intake…

"Would these modifications affect how the sparkling will finally come into this world? Would I-"

"No," Ratchet cut in, as if he didn't want Optimus to even entertain the thought. "The chamber's too high to even contemplate allowing the conduit to work as an emergence canal. I didn't install it with a natural delivery as an option. No. I'd remove it surgically directly through your chassis, as we'd already planned. It's the safest way."

Silence again, but it was a more peaceful kind than that which had punctuated this meeting thus far. Something resolved on both sides, some tension eased, though not all.

Optimus fidgeted his weight, readjusting his legs over the edge of the dam. The inscribed discs that bracketed his helm twitched in quarter circles. "Ratchet… As my friend, if you're disconcerted by this… If you feel that this is going too far for you…"

Ratchet shook his head before a possible end to that sentence could be sought. He placed a steady hand on the taller mech's shoulder, his grip solid and assured. "I'm in, Optimus. Whatever happens, I'm here. In whatever capacity you need or want me."

The Prime bowed his head with a thin smile. The 'thank you' was both implicit and unnecessary.

* * *

><p>It had been a relief the first time Ironhide had overloaded against him, inside him, shouting his pleasure with an expression bordering on pain as his own body had clenched impossibly tighter. The raw emotion of it, as much as the physical pleasure, had triggered Optimus's own, blasting apart a wall he hadn't been aware of.<p>

He had not experienced his body like this for two years. His overloads has been proscribed, his interfacing components bent solely towards sparking. He'd forgotten what it was like to feel this for mutual pleasure, for the few moments of utter and shared abandonment, uncluttered by hope or grief. Ironhide knew nothing of the endeavor, was here solely for companionship and mutual pleasure. And now, with the tearing malformation in his valve repaired, Optimus was experiencing interfacing in a whole new way. It was intense and exhilarating. Almost overwhelming.

Pressing his jaw against Ironhide's helm, Optimus found that his battle mask had extended to guard his face without his notice. He withdrew it, and lay a kiss against the unconscious specialist's crest in apology.

Not so unconscious, though. The small touch of his mouth, amidst all the shifts and twitches of his body, was enough to rouse the other mech.

As normal, Ironhide remained still and dark for the ten seconds it took to check for general alerts from the Base's computer, perform a perimeter scan and a run a check on his own systems. Then, satisfied that it was safe to continue to focus entirely on the mech beneath him, he purred a contented rumble.

As was also normal between them as of late, he picked straight up where they'd left off in their conversation.

"Meant to say earlier." Ironhide paused to flare his plates, stretching out the charge-loose workings underneath. His optics remained dark, his helm tucked into the Prime's collar. "Want'a get you and that battlebridge out on the range sometime tomorrow. Synch might've slowed for all that new programming Wheeljack's stuffed into it."

Optimus continued to play finger and thumb over Ironhide's dorsal vents, humming assent. He doubted that Wheeljack would have deemed the modifications finished if there were a lag, but he appreciated the specialist's meticulousness. Milliseconds counted in battle, particularly when facing Megatron. After centuries of warfare, they knew each other's strikes and feints as well as their own. One misstep in the rhythm, one persisting distraction in the forest…

"It's an ingenious system," he uttered, breaking from that potentially grim reverie. He would not lie here and think about death.

Ironhide grunted a sound close to a scoff. "Memory bank of an officer's sent and saved in the databank when they're offlined - until someone higher up goes and overrides them."

"It's strategy." Optimus rubbed a hand across his forehelm, wishing that this wasn't the topic of idle, post-overload talk. Tension was creeping back where minutes ago he'd been strutless. "It's not-"

"It's sick," Ironhide bit out, cut through with a venomous streak of static. He lifted his bulk off the Prime's chassis to look down at him, optics glaringly bright in the darkened room. "Ranking mecha's worth, their lives, like a requisitions list."

Optimus said nothing, and there was some edge of vulnerability in his gaze that tempered his ire. This was the absolute wrong time to have this conversation, mingling work with private affairs. More than that, it would never be appropriate to butt their professional and military mettle against one another whilst so intimately entwined.

He shook his head, pulsing apology into their still-mingled fields. "Just sayin'." A flicker of grim humour, and Ironhide had to elaborate when Optimus gave a querying frown. "Made me think of… Well, imagine it'd be something Prowl would do."

"Actually, I think it was a 'something' Prowl had written that Wheeljack worked from," Optimus replied dryly.

Ironhide's optics flashed in a proxy eye-roll, diffusing where he could easily rise. "Tactical."

There looked to be a difficult officer's meeting this afternoon. For now, though, and with Ironhide propping himself up on his elbows, Optimus took the opportunity to flex his backstrut in a long, slow wave. The innocent motion put his interface panel into dragging contact with the other mech's. A thick, heady jolt across his sensitised nodes made his fan stutter.

They were both the picture of debauchery: streaked with lubricant and transfluid, paint transfers clashing where their armour had ground and slammed. If it hadn't been for propriety, they'd have given up buffing out the marks days ago.

Ironhide's expression remained calculatingly neutral as he moved his hand, replacing his thigh against Optimus's panel, but his field throbbed with arousal. He palmed the still-pressuring spike as soon as it emerged, smiling when a twist to the base made Optimus arch with a groan.

"Ratchet'll have your mesh if you walk into a table again tomorrow 'cause I aint letting you recharge enough." The solid, pumping grip conveyed no apologies. "Bet he worries you've been agonising over a desk through the night."

Optimus hissed and clutched at Ironhide's collar faring, marvelling at how fast and thoroughly the charge built through his saturated lines. "I could just tell him the truth. He often hounds me for not getting - ahh- enough R and R."

"What'd' those stand for?" Ironhide rumbled, dipping his helm to taste and tease static off a finial. "Rutting and repeating?"

"Riding and roughly, perhaps," Optimus suggested in a near subsonic murmur, hips twitching into Ironhide's hand before he rolled and pressed the mech onto his back.

Straddling the powerful waist, Optimus continued to rock into his partner's ministrations. A snick of shifting metal, and he was grinding his exposed valve into Ironhide's panel.

Ironhide groaned, helpless to the sight, and took the Prime's hips in both hands. He pulled him into the next short thrust, and then the next. The pressure on his covered spike was astounding, and he couldn't have kept it back when Optimus rolled his hips like that if Megatron himself had burst through the door.

The slide in was glorious: slick and hot and entirely uninhibited. They'd done this a dozen times in the last week, but Optimus knew it would still feel this good if it were the thousandth. His helm tipped back, mouth open and vents howling, Between his knees, Ironhide looked much the same.

"Primus, I could do this all day," the specialist growled when the initial euphoria passed, optics bright on the powerful form that rocked in pleasure above him.

In the distant past their coupling had been just as exquisite, but there had been next to no penetration on Optimus's part. That had been fine: fragging was fragging in Ironhide's book, though he had never favoured taking spike. This complete turnaround had been suspicious at first, but having let Optimus initiate and goad him on faster and harder, he'd not questioned it.

Optimus certainly seemed content to drag him along for the ride.

He braced his pedes and drew up his knees, gaining leverage, and began to meet the rolling thrusts halfway. It was deep like this. When a ripple of current tripped across where his spike met the valve's ceiling nodes, Ironhide bucked up hard with a shout.

All too aware of Optimus's discomfort in the past, Ironhide was alert to pained grimaces or awkward hitches. When the tall mech stiffened, one hand dragging down his central seam whilst the other trembled against his knee, he froze, locking his joints against so much as a twitch. "Frag, too hard? Hurt?"

Optimus shot him a look that was almost comical, frustration that Ironhide had stopped clear in every line of his face. "No!" He tipped his head back, trying to regain the moment, and ground his hips down in search of that golden electric connection. "Ah, more. That. Again."

Ironhide grinned with a fresh pulse of charge, thoroughly enjoying the view of the Prime writhing on his hips. He slid his hands up powerful thighs, the constricting pressure around his spike as the charge ramped up ever higher becoming its own kind of delicious torment. "Yes, Sir."

* * *

><p><em>1 month, 3 weeks ago.<em>

* * *

><p>Ratchet had recommended that Optimus remain conscious during the modification of his 'reproductive equipment', citing the same risks and benefits as he had back when the gestation chamber had been installed. Optimus suspected that Ratchet was just giving him as many opportunities as possible to back out of the procedure.<p>

With his pedes braced and legs spread on an adapted berth in the Medbay, he was entertaining the idea of doing just that.

It was 2am and the base around them was dark and quiet. Optimus was all too aware of the sounds of Ratchet's equipment as he checked each item once more before setting it back on the tray on the neighbouring berth.

Connecting his valve and gestation chamber was not at all invasive, as he had originally thought. The medic planned to use the same technique used to replace crushed hoses buried deep in a mech's system that they would otherwise require significant excavation. A pilot wire was led through one incision and out of another, navigated through the body with an electromagnet that would hold the cutting point in position across three axis, and then the new hosing was clipped on the end and pulled through. Before the connecting channel could be laid, however, the top of the valve had to be prepared.

And those tools hadn't looked particularly appealing, even if all the neural lines in his pelvis had been dampened. The auger was narrow, at least, its edges bluntly rounded for insertion. Ratchet hadn't told him that scalpel-thin blades would extend once the tool was positioned, but Optimus was familiar enough with the device as used as an instrument of torture by certain Decepticons. Nothing first hand, but the reports had stuck with him.

Once the auger had been thoroughly sterilised and coated with a thick nanite gel, Ratchet returned to the stool placed between the Prime's knees. His optics had taken on the orange hue of surgical scanners, the discolouration symptomatic of slaving a patient's sensors for maximum diagnostic detail.

"Alright, Optimus," he said, placing a hand on the inside of his thigh. "You'll feel some hard pressure as I shape the cervical juncture, but if you feel _any_ discomfort, you must tell me immediately."

The angle of the berth, intended to drain spilt fluids out into the waiting receptacle, meant that Optimus could watch if he so chose. He did not, and gave a single nod of understanding before tipping his helm back.

A thumb at his valve, applying pressure, and then the auger was pushed inside. It didn't hurt, exactly, but the helix ridges caught and dragged like a breaching of a spike. He felt it scraping across his mesh, could imagine it snagging and tearing even if his sensory nodes were deadened. Stinging cuts in this most intimate place, all the way to the back of his valve, laid raw in anticipation of a thrusting spike and scalding fluid.

His hands curled into fists at his sides, his gaze focused with grim determination on the too-bright strip lights overhead. A tinny vibration rattled across the armour of his legs before he could suppress it.

Ratchet paused with the auger a scant few inches inside. "Are you alright? Do you want me to stop?"

Optimus blinked and shook his head, exventing slowly. "No, Ratchet, please continue." When Ratchet said nothing, he added, "I'm just not entirely, comfortable, with that part of my anatomy."

The self-depreciating reassurance fell flat, and Ratchet studied the underside of the mech's jaw and face guard. He didn't move the auger, and chose his words with the same calculated lightness. "All spike, huh?"

"It's not that I never tried. It was just..." He bit off the rest of the admission, frowning at himself. He had willingly lain on a berth in a less-equipped medical bay than this one and had several tonnes of his protomass torn out for the sake of installing an artificial organ, and hadn't fet like this. The thought of tools entering and interfering with his valve, however, made his tank churn.

Ratchet's optics were narrowed. He continued fishing with a light hand. "Unsatisfying?"

"It hurt."

The average medic had two reactions to a statement of pain: if they were aware of the cause and satisfied with its banality, it was dismissed; if they didn't know the cause and there was opportunity to seek it out, the full terrifying force of their vocation came to bear.

"Hurt?" Ratchet swiftly withdrew the auger and stood to set it aside. "Psychosomatic, do you think, or was there some pre-existing malformation or trauma?"

Optimus leaned up on his elbows as the medic came to stand next to him, doubtless scrutinising his readings and medical history whilst trying to be reassuring. "I assumed psychosomatic - something related to the Matrix, perhaps. How my body was reformatted. It was intimated that I would be more 'dominant'." An optical ridge twitched upwards, his expression dry. "It's not like there was any literature on the subject of Prime interfacing."

"No, I'd assume not. Since that long ago…" Ratchet drummed his fingers in a wave on the edge of the berth, left and then right. "What's the pain like? Bruising? Crushing? A burn?"

"Like I was being torn."

The medic stiffened as if somehow personally affronted, and purposefully set the instrument tray aside. "Well we definitely can't be having that."

"This is hardly necessary." Optimus sat up, trying to move his pedes only to find they were clamped into the stirrups. He settled for closing his knees, awkward as the posture was. "We don't need to waste time or resources on something I have long become accustomed to. My personal comfort isn't a factor in this endeavour."

"It most certainly is. Perhaps the most important factor," Ratchet huffed, the shielding plates across his shoulders flaring. He could cover a patient's body in an explosion as well as Ironhide could, and it came off more intimidating than protective when it suited.

Before Optimus could find some protest to that, Ratchet placed a hand on his arm and let the concern in his professionally controlled field be felt in the touch. "You're my patient, my Prime and my friend, Optimus. I won't have you suffering needlessly." A wry smile made him look younger. "Besides, when we get down to the bolts of it, you're carrying my sparkling. Keeping you comfortable is a natural part of my role, quite aside from anything else."

Withdrawing his hand, Ratchet's expression sobered. "Saying that, with your permission, I'd like to examine you more thoroughly."

Optimus was silent for almost a minute, though not because of his reluctance. He turned Ratchet's words over in his mind, contemplated the emotionally-weighted 'my sparkling' and 'my role', and wondered if the line in the sand had already been swept away. And if that was an issue.

Finally, he uttered, "If you feel it's necessary."

"You're more anxious about receiving into your valve than you are about carrying a sparkling to term," Ratchet said, sounding borderline bemused. "This is clearly a problem that's gone on far too long."

The examination was far gentle than the auger had been. After bringing his neural lines back online, Ratchet traced and retraced every millimetre of his valve in gradually deepening circles. His gaze was distant and to one side, his focus entirely on the sensitive plates in his fingertips as he searched for abnormalities.

Optimus watched Ratchet not watching, waiting for the sharp lance of heat that felt as if it cut through the entirety of his valve. When it came, he was so focussed upon the sensation that he hissed. "Ah, there."

"I feel it." Ratchet kept his index finger on the spot, and there was a transforming sound as two digits on his other hand shifted into long, slender tools. "It's a micro-fissure over a raised sensor node - it must rupture every time you've tried." He wouldn't have found it if Optimus hadn't reacted, and he didn't want to lose it and have to repeat the process.

The pain became sharper, more focussed, strange and deep. Optimus shifted on the berth, plates tightening. "Ratchet-"

"I know, I'm sorry, but I need to fix this now," Ratchet said with urgent determination, forcing the probe into the underlying node to find what was distending it. The result was reassuringly simple. "Ah, it feels like some idiot put too thick a weld on the relay under your coolant regulator. All I need to do is shave off the excess and it'll stop the node from being distended and tearing from contact. I can do it now."

He sent a short line of a code wreathed in medical overrides into the mech's systems, then held the tools exactly in place whilst they waited for the localised neural suppressor to take effect. When Optimus relaxed fractionally, he slid the second tool alongside the first and began scraping at the ragged weld.

"Primus, Optimus, I've been your medic since the Exodus." A gentle burst of cleanser flushed away the flakes of metal, and Ratchet resumed reshaping the weld. "Why didn't you ever tell me?"

Optimus continued to watch the ceiling. "It was not exactly a priority repair in war," he replied, perfectly serious.

Ratchet made a sound midway between a huff and a scoff; relatively mild on the medic's indicative scale of exasperation. "Perhaps not then, but it becomes one if we're trying for a sparkling." He withdrew the file and cleanser nozzle, then circled his finger over the area. It felt altered enough, but Optimus wouldn't be able to tell him if the repair was complete for a few days, once the soreness settled.

Satisfied for now, Ratchet withdrew his hands. He would have removed the stirrup clamps as well, but the valve modification needed to take place today. "Any kind of discomfort like this in the future, you come to me. Alright? I mean it."

Despite himself, Optimus smiled a little at the protectiveness in the assertion. He sat up on his elbows again, watching Ratchet reshuffle his equipment. "It's reassuring to know you have a vested interest in my interface equipment."

Ratchet definitely snorted this time, and his retort was equally dry. "I have a vested interest in your personal wellbeing." A nod to the reclined mech, who was reaching a hand towards the clamp keeping his right pede in the stirrup. "There's still work to do. Lie back."

"And think of Cybertron," Optimus concluded in a mutter, lacing his hands across his chassis.

* * *

><p><em>I'm sorry that this chapter took so long to appear. I've not abandoned any of my Transformers stories, but my circumstances have changed dramatically from when I began them all. I'll keep plugging away, and all I can say is thank you for sticking with me and reading! It'd be great to hear back from you =)_


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